r 


_ru_n-_n_-rv— n__n. 


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Works  of  Prof.  Robt  H,  Thurston. 

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OF  THE 

TJNIVERSIT^ 

•OIW41* 


A    TREATISE 


ON 


BRASSES,  BRONZES, 


The  Publishers  and  the  Author  will  be  grateful  to 
any  of  the  readers  of  this  volume  who  will  kindly  call 
their  attention  to  any  errors  of  omission  or  of  commission 
that  they  may  find  therein.  It  is  intended  to  make 
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rarely  happens  that  the  early  editions  of  works  of  any 
size  are  free  from  errors ;  but  it  is  the  endeavor  of  the 
Publishers  to  see  them  removed  immediately  upon  being 
discovered,  and  it  is  therefore  desired  that  the  Author 
may  be  aided  in  his  task  of  revision,  from  time  to  time, 
by  the  kindly  criticism  of  his  readers. 

JOHN   WILEY  &   SONS. 
53  EAST  TENTH  STREET. 


(UNIVERSITY) 


NEW   YORK: 

JOHN    WILEY   &   SONS,    PUBLISHERS, 

53  EAST  TENTH  STREET. 

1893 


H    -8. 

»1 

u   I 


4 


A    TREATISE 


ON 


BRASSES,  BRONZES, 


AND   OTHER 


ALLOYS, 

AND    THEIR 

CONSTITUENT     METALS. 


PART    III. 

MATERIALS    OF    ENGINEERING. 


BY 
ROBERT  H.  THURSTON,  LL.D.,  DR.  ENGINEERING, 

DIRECTOR    OF    SIBLEY    COLLEGE,   CORNELL    UNIVERSITY  j    FIRST  PRESIDENT  AMERICAN  SO- 

CIETY OF  MECHANICAL  ENGINEERS:  MEMBF.R  OF  AMERICAN  SOCIETY  CIVIL  ENGINEERS; 

AMERICAN  INSTITUTE  MINING  ENGINEERS;  SOCIE'TEDES  INGE*NIEURSCIVILS;  VEREIN 

DEUTCHER  INGENIEURE;  OESTERREICHISCHER^NGENIEI  R-  UND  ARCHITEKTEN 

VEREIN  ;  INSTITUTION  OF  ENGINEERS  AND  SHIPBUILDERS  IN  SCOTLAND  ; 

BRITISH    INSTITUTION    OF    NAVAL   ARCHITECTS  ;    FELLOW    OF 

AM.  Assoc.  FOR  ADVANCEMENT  OF  SCIENCE;    NEW 

YORK  ACADEMY  OF  SCIENCES, 

ETC.,  ETC.,  ETC. 


SECOND  EDITION, 


NEW   YORK  : 

JOHN    WILEY   &   SONS,    PUBLISHERS, 

53  EAST  TENTH  STREET. 

1893 


COPYRIGHT,  1884, 
BY  ROBERT  H.  THURSTGN. 

COPYRIGHT,  1889, 
BY  ROBERT  H.  THURSTON. 


Press  of  J.  J.  Little  &  Co. 
Astor  Place,  New  York 


CONTENTS. 


CHAPTER  I. 

HISTORY  AND  PROPERTIES  OF  THE  METALS  AND  THEIR    ALLOYS. 

ART.  PAGH 

1.  Ancient  knowledge  of  Metals 3 

2.  Metallurgy,    Schedule  of  Chemical  Processes 5 

3.  Calcination  and  Roasting 9 

4.  Smelting 1 1 

5.  Fluxes *.\N. . 12 

6.  Fuels 13 

7.  Mechanical  Processes 13 

8.  Working  of  Metals H 

9.  Metal  defined 1 6 

10.  Useful  Metals 16 

1 1 .  Laws  of  Ore  Distribution 17 

12.  Requirements  of  the  Engineer 17 

13.  Special  Properties  of  Metals 18 

14.  Non- Ferrous  Metals 19 

15.  Relative  Tenacities 19 

16.  Hardness .' 20 

1 7.  Conductivity 21 

1 8.  Lustre 24 

1 9.  Densities  and  Weights 25 

20.  Ductility  and  Malleability 27 

21.  Odor  and  Taste 28 

22.  Characteristics  in  General 30 

23.  Crystallization 30 

24.  Specific  Heats 31 

25.  Expansion  by  Heat 34 

26 .  Fusibility,  Latent  Heat 36 

27.  Chemical  Character 39 

28.  Alloys 39 


VI  CONTENTS. 

CHAPTER  II. 

THE    NON-FERROUS    METALS. 

ART.  PAGE 

29.  Copper,  History  and  Distribution 42 

30.  Qualities  of  Copper 43 

3 1 .  Ores  and  Sources 44 

32.  Processes  of  Reduction 47 

33.  Details 47 

34.  Properties  of  Copper 54 

35.  Commercial  Copper 55 

36.  Sheet  and  Bar  Copper 59 

37.  Tin,  Sources  and  Distribution 64 

38.  Reduction  of  Ores 64 

39.  Commercial  Tin 66 

40.  Zinc,  History  and  Sources 40 

4 1 .  Ores  of  Zinc,  Smelting 41 

42.  Metallic  Zinc 73 

43.  Lead 77 

41.  Ores  of  Lead 78 

45.  Smelting  Galena 79 

46.  Commercial  Lead 8 1 

4  7.  Antimony 82 

48.  Bismuth  and  its  Ores 83 

49.  Nickel  and  its  Ores 84 

50.  Uses  of  Nickel 86 

5 1 .  Aluminium 88 

52.  Mercury 90 

53.  Platinum 92 

54.  Magnesium , 94 

55.  Arsenic 95 

56.  Iridium  . . 96 

57.  Manganese 87 

58.  Rare  Metals 98 

59.  Commercial  Metals,  Prices 99 

CHAPTER  III. 

PROPERTIES     OF    ALLOYS. 

60.  General  Characteristics 102 

6 1.  Chemical  Nature  of  Alloys 104 


CONTENTS.  Vll 

LRT.  PAGE 

62.  Specific  Gravity  ....................................  108 

63.  Fusibility  ..........................................  no 

64.  Liquation  .........................................  113 

65.  Specific  Heat  ......................................  1  16 

66.  Expansion  by  Heat  .................................  1  1  6 

67.  Thermal  Conductivity  ...............................  1  1  8 

68.  Electric             "           ...............................  120 

69.  Crystallization  ..............................  .  .......  123 

70.  Oxidation  .........................................  1  24 

71.  Mechanical   Properties  ...............  ........  .......  126 


CHAPTER  lYjWIVERSITT 

THE    BRONZES. 

72.  Copper  Alloys  ;  Bronze  and  Brass  defined  ..............  130 

73.  History  of  Bronze  ..................................  131 

74.  Copper-Tin  Alloys   .................................  134 

75.  Properties  .........................................  136 

76.  Principal  Bronzes  ...................................  137 

77.  Early  Bronzes  ......................................  139 

78.  Oriental  Bronzes  ...................................  140 

79.  Density  of  Bronze  ..................................  141 

80.  Quality  of  Ordnance  Bronze  ..........................  141 

81.  Phosphor-Bronze  ...................................  143 

82.  Uses  of  Phosphor-Bronze  ...........................  145 

83.  Table  of  the  Bronzes  ................................  149 

'  "»" 

CHAPTER  V. 

THE    BRASSES. 

84.  Brass  defined  .................................  .....  158 

85.  Composition  of  Brass  ................................  158 

86.  Mallett's  Classification  ...............................  159 

87.  Uses  of  Brass  ......................................  1  59 

88.  Muntz  Metal  .......................................  160 

89.  Special  Properties  ...................................  161 

90.  Application  in  the  Arts  ...............................  162 

91.  Working  Brass  ......................................  163 

92.  Properties  or  Brass  .................................  165 


Vlll  CONTENTS. 

CHAPTER  VI. 

THE    KALCHOIDS   AND    MISCELLANEOUS    ALLOYS. 

ART.  PAGE 

93.  Use  of  various  Alloys 172 

94.  Copper-Tin-Zinc  Alloys 172 

95.  "      Iron  and  Zinc , .    174 

96.  "         "       "      Tin 174 

97.  Manganese-Bronze 175 

98.  "  "         Preparation 176 

99.  Aluminium     " 178 

100.  "  "         Uses 1 80 

101.  Copper-Nickel  Alloys 181 

102.  "  "      and  Zinc  (German  Silver) 182 

103.  "       andiron 183 

104.  ".     Antimony 185 

105.  "         "     Bismuth 186 

106.  "     Bismuth  ;  Bismuth-Bronze 186 

107.  "         "     Cadmium 186 

1 08.  "         "     Lead 187 

109.  "         "     Silicon 187 

1 10.  "         "         "       ;  Silicon-Bronze 188 

in.  "     Tin  and  Lead 188 

112.  "       "     Antimony  and  Bismuth 188 

113.  "       "     Zinc  and  Iron 189 

1 14.  "       and  Mercury ;  Dronier's  Alloy 189 

115.  Complex  Copper  Alloys 189 

1 1 6.  Bismuth   Alloys 1 90 

1 1 7.  Tin  and  Lead  ;  Fusible  Alloys 193 

1 1 8.  Lead  and  Antimony 193 

119-  Tin      "  "         198 

120.  "         "     Lead ;  Fusible  Alloys 198 

121.  "         "     Zinc 201 

122.  Antimony,  Bismuth  and  Lead 202 

123.  Tin  "         "     202 

124.  "  "  "       Zinc 202 

125  "   Bismuth  and  Lead 202 

1 26.  Pewter  and  Britannia  Metal 205 

127.  Iron  and  Manganese 202 

1 28.  Platinum  and  Iridium 203 

129.  Spence's  "  Metal  " , 204 


CONTENTS.  ix 

CHAPTER   VII. 

MANUFACTURE    AND    WORKING    OF    ALLOYS. 

ART.  PAGE 

130.  Alloy  of  General  Use  ;  Brass  Working 205 

131.  The  Brass  Foundry 207 

132.  Melting  and  Casting 207 

133.  Furnace  Manipulation 209 

134.  Preparation  of  Alloys 210 

135.  Effect  of  Small  Doses  of  Metal 212 

136.  Art  Castings  in  Bronze 212 

137.  Stereotyping 214 

138.  German  Silver 215 

1 39.  Babbitt's  Anti- friction  Metal 515 

140.  Solders 216 

141.  Standard  Compositions 218 

142.  Special  Recipes 221 

143.  Classified  Lists . . .  < 226 

144.  Bronzing 237 

145.  Lacquering 239 

CHAPTER  VIII. 

STRENGTH    AND   ELASTICITY   OF    NON-FERROUS   METALS. 

146.  Strength  of  Non-Ferrous  Metals 242 

147.  Resistances  Classified , 242 

148.  Factors  of  Safety "  244 

149.  Measures  of   Resistance   * 246 

1 50.  Methods  of  Resistance 247 

151.  Equation  of  Resistance  Curves 248 

152.  The  Elastic  Limits 249 

153.  Impact,  Shock 251 

154.  Resilience 252 

155.  Proportioning  for  Shock 255 

156.  Methods  of  Test 255 

157.  Compression 255 

158.  Structure  and  Composition 256 

1 59.  Transverse  Stress 256 

160.  Distribution  of  Resistances 258 

1 6 1 .  Theory  of  Rupture 259 


X  CONTENTS. 

ART.  PAGE 

162.  Formulas  for  Transverse  Loading «...  260 

163.  Modulus  of  Rupture 262 

1 64 .  Elastic  Resistance 263 

165.  Torsional       "          267 

1 66.  Strength  of  Shafts 268 

167.  Tenacity  of  Copper 270 

168.  Tests         "        " 271 

169.  "  "  Commercial  Copper. 272 

1 70.  Shearing  Resistance               "    ,  277 

171.  Resistance  to  Compression 278 

1 72.  Compression  by  Impact 281 

1 73.  Transverse  Tests  of  Copper 284 

1 74.  Modulus  of  Elasticity 286 

1 75.  Copper  in  Torsion . . 287 

176.  Mean  of  Results  of  Tests  of  Copper 287 

177.  Strength  of  Tin 288 

178.  Transverse  Resistance  of  Tin 292 

179.  Modulus  of  Elasticity  of  Tin 294 

1 80.  Tin  in  Torsion 294 

1 8 1.  Strength  of  Zinc 296 

182.  Tests  of  Zinc 297 

183.  Various  Metals 298 

184.  Wertheim  on  Elasticity 300 

185.  BischofFs  Tests 303 

CHAPTER  IX. 

STRENGTH    OF    BRONZES    AND    OTHER    COPPER-TIN    ALLOYS. 

1 86.  The  Bronzes  defined 306 

187.  Tenacity  of  Gun  Bronze;  Wade's  Experiments   306 

1 88.  "          "     "          "         Anderson 308 

189.  "         "  Bell  Metal,  Mallett 308 

190.  Ordnance  Bronze  in  Compression 309 

191.  Hardness  of     "  (Riche) 311 

192.  Tenacity  of  Phosphor-Bronze 312 

193.  Resistance  "      to  Abrasion 316 

194.  Strength  of  Manganese- Bronze 316 

195.  Manganese-Bronze  under  Impact 317 

196.  Strength  of  Ferrous  Copper. 319 


CONTENTS.  XI 

ART.  .  PAGE 

197.  Copper-Tin  Alloys,  U.   S.  Board 320 

198.  Metals  used  in   Research ...  322 

199.  Alloys  tested. '.*>• 322 

200.  Temperatures  of  Casting '  ^^  ,  ^^^  .  .  -  324 

201.  External  appearance  of  Test  Pieces^f^^^^^^x.  325 

202.  Behavior  under  Test. ^tXNl.VJCiRsicp-y:  .•  326 

203.  Appearance  of  Fractures •v^^^fFOtHNlA^x**  33° 

204.  Records  of  Test ."TTrTTTT. . .  335 

205.  Final  Results. 341 

206.  Strain- diagrams  of  Bronzes  in  Tensions 344 

207.  Tenacities  of  Bronzes. 344 

208.  Strain-diagrams  of  Bronzes  in  Compression 346 

209.  Transverse   Strain-diagrams 348 

210.  Comparison    of  Resistances '. 350 

211.  "    Resiliences 353 

212.  "   Specific    Gravities 355 

213.  "             "    Elastic  Limits 358 

214.  "             "    Moduli  of  Elasticity 361 

215.  "             "    Ductilities     361 

216.  "             "   Conductivities 363 

217.  "             "  Hardness,  etc ; . .  363 


CHAPTER   X. 

STRENGTH    OF    BRASSES    AND    OTHER    COPPER-ZINC    ALLOYS. 

218.  The  Brasses  denned : 366 

219.  Earlier  Experiments. . 367 

220.  Strength  of    Sterro-metal 368 

221.  Moduli  of  Elasticity 368 

222.  Copper-Zinc  Alloys  tested  for  the  U.  S 369 

223.  Alloys  tested 370 

224.  Appearance  of   Test-pieces 371 

225.  "  "     Fractures 373 

226.  Temperatures  of  Casting - 275 

227.  Mixtures  and  Analyses 376 

228.  Results  of  Tests 378 

229.  Conclusions  from  Tests 379 

230.  Notes  on   Tests 383 

231.  Tenacity  of  Brasses 384 


xii  CONTENTS. 


232.  Resistance  to  Compression 385 

233.  "           "  Transverse  Stress 387 

234.  "           "  Torsion 391 

235.  "         of  Shafts 392 

236.  Records  of  Tests 393 

237.  Strain-diagrams  of  Tension 404 

238.  "           "         "    Transverse  Tests 406 

239.  Resistances  compared 406 

240.  Resiliences                         409 

24 1 .  Elastic  Limits      "             409 

242.  Moduli                               411 

243.  Specific  Gravities  compared 412 

244.  Ductilities    412 

245.  Summary 413 

CHAPTER   XI. 

STRENGTH  OF  THE  KALCHOIDS  AND  OTHER  COPPER-TIN-ZINC  ALLOYS. 

246.  The  Kalchoids 4 14 

247.  Sterro-metal 415 

248.  Copper-Tin-Zinc  Alloys 416 

249.  Plan  of  Research 416 

250.  Selected   Alloys 418 

251.  Details  of  Investigation 419 

252.  Method  of  Registry 425 

253.  General  Deductions 427 

254.  Strain  Diagrams 429 

255.  Tenacities 430 

256.  Ductility 434 

257.  Improvement 437 

258.  Thurston's  "  Maximum  "  Bronzes 440 

259.  Results  of  Tests 442 

260.  Discussion 443 

261.  Conclusions 446 

262.  Other   Researches 447 

CHAPTER  XII. 

THE    STRENGTH    OF    ZINC-TIN    AND    OTHER    ALLOYS. 

263.  Zinc-Tin  Alloys 449 

264.  Strength  and  Density 450 


CONTENTS.  Xlll 

A»T.  PAGE 

265.  Grey  Ternary  Alloys 450 

266.  Earlier  Investigations 45 1 

267.  Records  of  Tests 452 

CHAPTER  XIII. 

CONDITIONS    AFFECTING     STRENGTH. 

268.  Conditions  modifying  Tenacity  of  Non-Ferrous  Metals. ..  476 

269.  Heat                    "             "         "Copper 476 

270.  "                        "              "         "    Bronze 477 

271.  "                        "              "         "    Various  Metals 480 

272.  "                        "        Elasticity 480 

273.  Stress  produced  by  Change  of  Temperature 481 

274.  Effect  of  Sudden  Variation    "             "           482 

275.  "       "    Chill-Casting 483 

276.  "       "    Tempering  and  Annealing;  on  Density 484 

277.  "       "                          "                           on  Tenacity 487 

278.  "       "                       Temperature  of  Casting 488 

279.  "       "                       Time  of  Loading 489 

280.  "       "                       Prolonged  Stress  on  Tin  and  Zinc ...  492 

281.  Effect  of  Prolonged  Stress  on  Bronze 497 

282.  Fluctuation  of  Resistance 498 

283.  Effects  of  Intermitted  and  Steady  Stress  on  Resistance..  500 

284.  "        "                           Stress  on  Deflection 502 

285.  "        "             "                «       "   Elastic  Limits 508 

286.  "        "      Variable          "       "        "           ll      512 

287.  «        "      Repeated         "       "     Strength 515 

CHAPTER   XIV. 

MECHANICAL    TREATMENT    OF    METALS    AND    ALLOYS. 

288.  Qualities  affected  by  Mechanical  Treatment 517 

289.  The  Whitworth   Process. 519 

290.  The  Lavroff  Process 523 

291.  Rolling  and  Forging 5 24 

292.  Hydraulic  Forging  ;  Drop  Forging 525 

293.  Thermo-Tension  ;  Annealing 526 

294.  Cold-Working 527 

295.  Wire-Drawing 527 


XIV  CONTENTS. 

ART.  PAGE 

296.  Cold-Rolling   Iron  ;  Lauth's  Process 529 

297.  The  Dean  Process,  applied  to  Bronze 530 

298.  Uchatius'  Method 531 

299.  Experiments  on  Compressed  Bronze 538 

300.  Uchatius'  Deductions 540 

301 .  Frigo-Tension 540 

302.  Comparison  of  Methods 541 

303.  Effect  of  Rolling  and   Hammering 543 

304.  Historical ;  Discoveries 546 

305 .  History  of  Experiments 548 

306.  "       "   Exaltation  of  Elastic  Limits 552 

307.  et       "   Strain  Diagrams 55 1 

308.  "       "    Processes 552 

309.  Cold-Working  Iron 555 

310.  "           "        Bronze 556 

311.  Conclusions 557 


THE  MATERIALS  OF  ENGINEERING 


PART     III, 


NON-FERROUS   METALS. 


OF  THE 

XTHXVERSITY 


NON-FERROUS   METALS. 


CHAPTER     I. 

HISTORY    AND    CHARACTERISTICS     OF    THE    METALS    AND 
THEIR  ALLOYS.* 

I.  The  knowledge  of  metals  possessed  by  tne  early 
races  of  mankind  was  of  the  most  inexact  and  unsatisfactory 
character.  They  were  probably  led  to  seek  a  method  of 
utilizing  them,  first,  by  the  demands  of  their  fighting  classes. 
Their  structures,  their  implements  of  agriculture  and  war,  and 
their  domestic  utensils  were,  in  the  earliest  stages  of  their  race- 
history,  of  wood,  bone,  and  stone.  All  races  are  found  to 
have  advanced  to  their  present  condition  of  civilization  from 
a  primitive  state  of  barbarism,  in  which  they  were  entirely 
ignorant  of  the  use  of  metals,  and  knew  nothing  of  even  the 
simplest  processes  of  reduction. 

The  weapons  of  mankind,  in  prehistoric  times,  were  at  first 
made  of  hard  wood,  of  bone,  or  of  stone,  fashioned  with  long 
and  patient  labor  into  rude  and  inefficient  forms.  As  the 
race  advanced  in  knowledge  and  intelligence,  they  acquired, 
by  some  fortunate  circumstance,  a  knowledge  of  the  methods 
of  reducing  from  the  ores  the  more  easily  deoxidized  metals, 
and,  still  later,  those  which  cling  with  tenacity  to  oxygen, 
and  require  considerable  knowledge  and  skill,  and  special 
apparatus  for  their  reduction  to  the  metallic  state ;  and  at  a 
still  very  early  period,  they  applied  the  more  common  and 
more  generally  useful  metals  in  their  rude  manufactures. 

*  This  introduction  has  been  in  part  prefaced  to  Part  II.  on  Iron  and  Steel, 
as  the  volumes  are  published  and  sold  separately. 


4     MA  TERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

It  has  thus  happened,  that  mankind  has  passed  through 
what  are  designated  by  the  geologists  as  the  ages  of  stone, 
of  bronze,  and  of  iron,  and  may  be  considered  as  having  just 
entered  upon  an  age  of  steel. 

The  ancients,  at  the  commencement,  and  immediately 
before  the  Christian  era,  were  familiar  with  but  seven  metals. 

The  earliest  of  historical  records  indicate  that,  long  pre- 
vious to  their  date,  some  metals  were  worked,  although  with 
rude  apparatus,  and  in  an  exceedingly  unintelligent  manner. 
Tubal  Cain  was  an  artificer  in  brass  and  in  iron  ;  and  several 
sacred  writers  refer  to  the  use  of  these  metals  and  of  gold 
and  silver,  in  very  early  times.  Profane  writers  also  present 
similar  testimony ;  and  the  discovery  of  implements  of  metal 
among  the  ruins  of  the  ancient  cities  of  Asia  and  Africa,  and 
in  the  copper  mines  and  other  localities  of  North  America, 
indicate  that  some  knowledge  of  metallurgy  was  acquired 
many  centuries  before  our  era. 

The  Hebrews  were  familiar  with  gold,  silver,  brass 
(bronze  ?),  iron,  tin,  and  lead,  and  possibly  copper  and  other 
metals. 

Bronze  and  brass  were  not  always  distinguished  by  ancient 
writers,  but  both  alloys  were  known  at  a  very  early  date. 
Phillips  gives  analyses  *  of  a  number  of  samples  of  the  latter 
dating  from  B.C.  20  to  B.C.  165,  and  bronze  was  certainly 
made  much  earlier.  Zinc  was  known  in  the  metallic  state 
at  some  early  date,  while  tin  was  known  in  the  earliest  his- 
toric times. 

The  Chinese,  at  a  time  far  back  of  even  their  oldest  his- 
torical records  and  traditions,  seem  to  have  been  workers  in 
iron  and  in  bronze. 

Evidence  has  been  found,  in  Hindostan,  that  the  inhabit- 
ants of  the  Indian  peninsula,  at  an  era  of  their  history  of 
which  we  have  lost  every  trace,  were  able  not  only  to  reduce 
these  metals  from  their  ores  by  rude  metallurgical  processes, 
but  that  they  actually  constructed  in  metal,  works  which  are 
looked  upon  as  remarkable  for  their  magnitude. 

The  Chaldeans,  four  thousand  years  ago,  the  Persians,  the 

*  Metallurgy,  1874,  p.  6. 


HISTORY  OF  THE  METALS  AND  THEIR  ALLOYS.  5 

Egyptians,  and  the  Aztec  inhabitants  of  America,  if  not  an 
earlier  race,  had  some  knowledge  of  the  reduction  and  of  the 
manufacture  of  metals. 

The  "  Bronze  Age,"  in  Europe,  is  supposed  to  have  origi- 
nated in  the  south  of  England,  and  to  have  gradually  spread 
over  Europe,  a  knowledge  of  the  methods  of  working  copper 
and  bronze  finally  becoming  very  general.  The  bronze  age 
of  Central  America  antedated  that  of  Northern  America, 
where  the  contemporaneous  age  was  that  of  copper. 

It  is  probable  that  copper  may  have  been  the  first  metal 
worked  by  these  early  metallurgists,  and  that  tin  was  next 
discovered  and  used  to  harden  the  copper,  as  is  done  at  the 
present  time.  In  the  manufacture  of  bronze,  the  ancients 
became  very  skilful,  probably  long  before  the  discovery  and 
use  of  iron.  The  bronze  implements  discovered  on  both  con- 
tinents have  sometimes  nearly  the  hardness  and  sharpness  of 
our  steel  tools. 

It  is  only  within  a  comparatively  recent  period,  however, 
that  metallurgy  has  become  well  understood.  To  insure  its 
rapid  and  uninterrupted  progress,  it  was  necessary  that  the 
science  of  chemistry  should  be  first  placed  upon  a  solid  basis, 
and  this  was  only  done  when,  about  a  century  ago,  Lavoi- 
sier introduced  the  use  of  the  balance,  and  by  his  example 
led  his  brother  chemists  to  employ  exact  methods  of  re- 
search. 

2.  The  valuable  qualities  of  the  'metals  used  in  con- 
struction are  very  greatly  influenced  by  the  presence  of 
impurities,  and  by  their  union  with  exceedingly  minute 
quantities  of  the  other  elements,  both  metallic  and  non- 
metallic. 

In  the  processes  by  which  the  metals  are  reduced  from 
their  ores  and  prepared  for  the  market,  there  is  always 
greater  or  less  liability  of  producing  variations  of  quality  and 
differences  of  grade,  in  consequence  of  the  impossibility  of 
always  avoiding  contamination  by  contact  with  injurious  ele- 
ments during  these  operations,  even  where  the  ore  was  origi- 
nally pure. 

In  the  time  of  Lavoisier,  but  seventeen  substances  were 


6     MA  TERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

classed  as  metals,  and  of  these  the  characteristics  upon  which 
the  classification  was  based  were  principally  physical,  and  the 
place  of  newly  discovered  elements  was  long  uncertain ; 
potassium  and  sodium  were  at  first  (1807)  classed  as  non- 
metals. 

.  The  distinction  between  metals  and  metalloids  remains 
somewhat  indefinite,  and  the  type  metal  is  considered,  neces- 
sarily, ideal.  The  metals  are  usually  solid,  mercury  being  an 
exception ;  they  are  usually  liquefiable  by  heat,  but  arsenic 
is  volatile  without  fusing;  they  are  generally  opaque,  but 
gold  is,  in  very  thin  leaves,  translucent ;  they  are  nearly  all 
malleable  and  ductile,  but  in  very  variable  degrees.  The 
metals  are  good  conductors ;  the  metalloids  are  not.  The 
metals  are  electro-positive,  as  a  rule ;  the  metalloids  electro- 
negative. 

Metallurgy  is  the  art  of  separating  the  metals  from  the 
chemical  combinations  in  which  they  are  met  in  nature, 
freeing  them  from  impurities  with  which  they  may  be 
mechanically  mingled,  and  reducing  them  to  the  state  in 
which  they  are  found  in  our  markets,  and  in  which  they  are 
adapted  for  application  in  construction. 

The  chemical  combinations  from  which  the  useful  metals 
are  obtained,  are  usually  either  the  sulphides  or  the  oxides. 
The  common  ores  of  iron  are  peroxides,  either  hydrated  or 
anhydrous,  and  copper  is  generally,  except  in  the  Lake  Su- 
perior mining  region  of  the  United  States,  reduced  from  the 
state  of  sulphide. 

Lead  is  usually  found  combined  with  sulphur,  forming  a 
sulphide  known  as  galena. 

Zinc  is  found  and  mined  as  an  oxide,  as  a  sulphide,  and 
also  as  carbonate  and  silicate. 

The  sulphide  of  iron  is  rarely  or  never  mined  as  an  ore 
of  iron,  although  abundantly  distributed  in  the  form  of 
pyrites. 

The  following  table  *  illustrates  the  general  character  of 
the  chief  chemical  processes  employed  for  the  purpose  of 
reducing  metals  of  ordinary  occurrence  from  their  ores. 

*  Metals  and  Applications.     G.  A.  Wright,  London,  1878. 


HISTORY  OF  THE  METALS  AND   THEIR  ALLOYS.  7 

TABLE   I. 

REDUCTION   PROCESSES   IN  USE. 

I—  NATIVE  METALS. 

By  mechanical  means  .....   ......  e.g.  gold  washing. 

By  simple  fusion  (liquefaction)  ----  e.g.  bismuth. 

By  solution  in  mercury  ..........  e.g.  gold-quartz. 

By  solution  in  aqueous  chemicals.  .  e.g.  gold-quartz. 

II.  —  SIMPLE  ORES;  i.  e.,  containing  only  one  metal. 
A.—  OXIDES. 

Analytic  .....      By  simple  heating  ...............  e.g.  mercury,  silver. 

f  By  heating  in  hydrogen  ..........  eg.  nickel,  iron. 

Single  decom-  J  By  heating  in  carbon  oxide  .......  e.g.  iron  (blast  furnace). 

position  ...  1  By  heating    with    carbon   (coal,  \ff.\  tin,  arsenic,  zinc,  iron, 

L      coke,  etc.)  ..................  J    '  '  '   (      antimony. 

B.—  CHLORIDES,  FLUORIDES,  ETC. 

Analytic  .....      By  heating  alone  ................  e.g.  platinum,  gold. 

(By  heating  in  hydrogen  ..........  e.g.  silver. 
By  action  of  cheaper  metal,  etc. 
By  (tf)  wet  processes  .............  e.g.  copper,  gold. 
By  (b)  dry  processes  .............  e.g.  magnesium,    aluminium. 
By  (c)  amalgamation  processes  ----  e.g.  silver. 

C.  —  SULPHIDES. 

Single  decom-  j  By  heating  with  air  .............  e.g.  mercury,  copper,  lead. 

position  ...   \  By  heating  with  cheaper  metal,  etc.  e.g.  mercury,  antimony,  lead. 


. 

followed  by      B     converting'into  chloride  and)  n 

single      de-         y  reati      as*bove  ............  \*f>  Sllver' 

composition 


D.—  CARBONATES. 


Single  decom-  j  By  heating  with  carbon  ..........  e.g.  zinc,  sodium,  potassium. 


followed  by  4  By  converting  intochloride  and) 

single      de-         ytreating  asSabove  ............  r  *'      PP^ 

composition  L 

III.—  COMPLEX  ORES;  i.  e.,  containing  more  than  one  metal. 

I.  Alloy  extracted  by  some  or  )          j  silver-lead  alloy,  spie- 

other  process,  as  above.  ...  \    '  ''  (     geleisen. 
II.  Special  processes  adopted  for  ) 

extraction  of   metals  sepa-  V  e.g.  cupriferous  pyntes. 
rately  ....................  ) 


8      MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

It  is  not  the  purpose  of  the  Author  to  describe  these  proc- 
esses at  length. 

In  the  reduction  of  metallic  ores,  the  earthy  impurities 
are  separated  as  completely  as  possible  by  selection,  and  by 
mechanical  methods,  and  the  operation  of  smelting  follows, 
during  which,  by  chemical  processes,  the  remaining  impuri- 
ties, whether  mechanically  or  chemically  united  with  the 
metal  are  removed.  Earthy  matters  are  removed  in  the 
furnace,  by  the  use  of  properly  selected  and  skilfully  pro- 
portioned fluxes. 

The  ores,  in  their  then  purified  condition,  are  deoxidized 
by  the  action  of  carbon,  or  of  carbonic  oxide,  at  high  tem- 
peratures. The  sulphides  are  decomposed  by  burning  out 
their  sulphur,  as  it  is  usually  found  that  the  affinity  of  sul- 
phur for  the  oxygen  of  the  atmosphere  is  greater  than  for 
the  metal  with  which  it  is  found  in  combination. 

In  these  processes,  high  temperatures  are  requisite,  as 
the  chemical  reaction  to  be  secured  can  usually  only  occur 
satisfactorily  when  one  or  all  of  the  substances  treated  are 
in  either  the  liquid  or  the  gaseous  state. 

In  the  reduction  of  ores,  the  flux  must  be  melted,  as  must 
be  the  silica  with  which  it  is  to  unite,  and  which  it  is  to 
remove  from  the  ore,  before  this  desired  union  can  take  place  ; 
and  also  in  order  that  the  silicate  formed  may  flow  to  the 
bottom  and  out  of  the  tap  hole  of  the  furnace. 

The  oxide  left  after  the  removal  of  earthy  matters  must 
usually  be  brought  in  contact  with  carbon  in  the  gaseous 
state  as  carbonic  oxide,  to  insure  its  reduction ;  and  the 
finally  reduced  metal  must  be  retained  liquid,  in  order  that  it 
may  be  conveniently  removed  from  the  furnace. 

The  temperatures  required  and  allowable  in  reducing  the 
various  ores  are  widely  different.  Iron,  copper,  bismuth, 
lead,  and  nickel  are  reduced  at  a  bright  red  heat;  while  ores 
of  tin,  zinc,  and  manganese  must  be  made  white  hot — zinc 
being  volatilized  in  the  process  of  smelting. 

The  process  of  reduction  of  a  metal  from  its  ores,  and  its 
separation  from  earthy  or  metallic  impurities,  sometimes  con- 
sists of  a  single  operation,  sometimes  of  two  or  more. 


yE 

(UNIVERSITY. 

HISTORY  OF  THE  METALS  AiVD  THEIR  ALLOYS.  9 

3.  Calcination  or  Roasting. — The  first  process  to  which 
the  ore  is  subjected,  after  leaving  the  mine,  is  frequently  that 
of  Calcination  or  of  Roasting,  by  which  the  ore  is  disintegrated, 
and  during  which  sulphur,  carbonic  acid,  and  other  volatile 
elements  and  compounds  are  eliminated. 

In  this  process  the  ores  are  not  mixed  with  a  flux,  and 
the  temperature  is  not  raised  so  high  as  to  produce  either 
fusion  or  reduction.  This  is  found  to  be  an  economical  proc- 
ess with  nearly  all  ores  of  iron,  and  it  is  also  adopted  in  the 
reduction  of  lead  and  zinc.  The  operation  is  performed  either 
in  the  open  air  or  in  kilns.  The  former  method  is  adopted 
with  ores  capable  of  withstanding  somewhat  elevated  tem- 
peratures, such  as  the  ores  of  iron. 

Roasting  in  heaps  in  the  open  air  is  conducted  as  follows : 
The  ground  selected  is  first  covered  with  a  layer  of  wood,  or 
of  coal  six  inches  or  more  in  depth.  Over  this  is  spread  a 
layer  of  ore  from  one  to  two  feet  thick,  the  quantity  being 
determined  for  each  case  by  experience,  and  varying  with  the 
character  of  the  ore.  Another  layer  of  fuel  is  added,  and 
this  is  covered  with  another  layer  of  ore.  Alternate  layers 
are  thus  added  to  the  pile,  until  it  has  reached  the  desired 
height.  The  pile  is  then  fired,  and  the  ore,  under  the  action 
of  the  moderate  temperature  produced  by  the  smouldering 
fire,  is  slowly  roasted  and  becomes  well  prepared  for  the  suc- 
ceeding process  of  reduction. 

It  loses  its  water,  whether  of  combination  or  free,  gives 
up  its  carbonic  acid,  loses  a  portion,  if  not  all,  of  the  sulphur 
which  may  have  been  united  with  it,  and  the  disintegration 
produced  fits  it  for  more  thorough  intermixture  with  fluxes, 
and  for  more  rapid  and  complete  reduction. 

The  second,  and  the  most  usually  satisfactory,  method, 
with  iron  ores,  is  that  of  roasting  in  kilns. 

The  fuel  and  the  ore  are  charged  alternately  into  the  kilns 
in  such  a  manner  as  to  become  intimately  mixed,  and  the 
process  is  similar  in  all  respects  to  that  which  goes  on  in 
the  previously  described  method.  With  kilns,  however,  the 
operation  can  be  carried  on  continuously,  the  roasted  ore 
being  removed  at  the  bottom,  and  new  material  supplied  at 


10  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

the  top  as  required.  This  method  requires  comparatively 
little  space,  and  does  not  necessitate  the  accumulation  of 
immense  masses  of  ore  "  in  stock,"  as  does  calcination  by  the 
other  method.  The  expense  of  the  construction  of  the  kilns 
is  an  objection  which  is  usually  more  than  counterbalanced 
by  the  advantages  of  the  process. 

Roasting  to  produce  oxidation  is  a  common  process  in 
the  ordinary  work  of  reduction  of  sulphides  and  of  protoxides 
in  special  cases.  The  sulphides  are  usually  converted  either 
into  sulphates  or  into  a  mixture  of  sulphate  and  oxide,  of 
which  the  former  often  decomposes  at  high  temperature  into 
sulphurous  acid  and  oxide,  or  oxide  and  basic  sulphate,  as 
with  iron  or  zinc  ores.  Arsenides  and  phosphides  are  simi- 
larly treated. 

Roasting  to  volatilize  the  sulphur  is  a  common  method 
of  treatment  of  iron  pyrites,  which  yield  sulphur  freely  by 
partial  decomposition.  Carbonates  and  hydrated  ores  are 
also  thus  treated  to  drive  off  carbonic  acid  and  water.  The 
most  common  process  of  reduction  of  ores  is  a  refined  method 
of  reducing  by  roasting  in  a  deoxidizing  atmosphere,  and  in 
contact  with  other  reducing  agents,  as  carbon. 

The  metals  which  are  treated  of  in  this  work  are  all  usually 
found  only  in  a  state  of  combination  with  either  oxygen  or 
sulphur,  with  the  single  exception  of  copper,  which  is  often 
found  native,  and  deposits  of  which  are  sometimes  very 
extensive,  furnishing  the  market  with  large  quantities  of  that 
metal.  These  oxides  and  sulphides  are  mixed  with  other 
minerals  of  less  valuable,  of  valueless,  or  even  often  of  in- 
jurious, character.  It  becomes  usually  necessary  to  melt  the 
"  ores,"  as  these  minerals  are  called,  to  effect  the  separation 
and  reduction  of  the  metal.  This  operation  is  called  "  smelt- 
ing." The  "wet"  or  "  humid  "  processes  of  reduction  are 
but  little  practised  in  ordinary  metallurgical  work,  although 
those  methods  and  electrolysis  are  occasionally  found  useful 
and  commercially  economical. 

The  melting  of  common  ores  is  not  usually  practised, 
except  as  a  sequel  to  an  earlier  roasting  process,  except  in 
the  case  of  oxides  of  iron,  which  are  often  smelted  without 


HISTOR  Y  OF  THE  ME TALS  A ND  THEIR  ALLO  YS.          1 1 

calcination  or  roasting  except  such  as  occurs  within  the  furnace 
previous  to  fusion.  When  melting  does  take  place,  it  results 
in  reduction  of  the  metal  and  its  separation  from  the  gangue 
that  may  have  accompanied  it.  This  separation  is  usually 
accomplished  partly  by  the  formation  of  a  fusible  slag,  by 
union  of  the  gangue  with  a  flux,  which  is  either  siliceous, 
aluminous  or  calcareous,  according  to  circumstances. 

Melting  to  reduce  the  ore  is  effected  by  the  combined 
action  of  heat  and  of  chemical  affinity,  and  by  the  use,  with 
oxides  generally,  of  carbon  both  as  a  fuel  and  as  a  reducing 
agent.  Sulphides  of  other  metals  than  iron  are  reduced  by 
melting  with  that  metal.  Smelting  with  oxidation  some- 
times takes  place,  as  in  separating  metals,  or  removing  sulphur, 
or  in  the  manufacture  of  litharge,  a  lead  oxide ;  this  sub- 
stance is  also  used  as  an  oxidizing  agent  with  sulphides  of 
other  metals. 

Melting  to  effect  solution  is  sometimes  practised  to  secure 
a  separation  of  compounds  into  constituent  elements  or  com- 
pounds. Thus  fused  lead  oxide  dissolves  some  of  the  sul- 
phides and  many  oxides.  Lead  itself  is  used  in  dissolving 
silver  and  gold  out  of  some  of  their  ores.  The  alkaline  car- 
bonates dissolve  the  oxides  of  the  metals,  and  borax,  fluor- 
spar, and  other  substances  similarly  used  as  fluxes  act  in  the 
same  manner  when  employed  in  the  production  of  slags. 
The  silicates  of  alkalies  and  alkaline  earths  perform  the  same 
office  as  the  £ther  fluxes,  and  are  especially  valuable  in  the 
treatment  of  oxides,  as  solvents  both  of  some  oxides  and  of 
the  gangue  ;  the  most  easily  reduced  oxides  are  dissolved  by 
the  silicate,  and  go  into  the  slag,  while  the  less  readily  reduci- 
ble oxides  of  the  compound  give  up  the  metal.*  Slags  are 
necessarily  more  fusible  than  the  metal  to  be  reduced. 

Melting  is  often  a  process  preliminary  to  volatilization,  as 
in  the  reduction  of  ores  of  arsenic  and  of  zinc,  or  to  separa- 
tion by  liquefaction  and  crystallization. 

4.  Smelting". — The  final  process  of  reduction,  that  of 
Smelting,  which  usually  requires  still  higher  temperature, 
and  which  immediately  succeeds  calcination,  is  conducted  in 

*  Watts. 


12    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 

various  ways,  the  outlines  of  which  will  be  given  in  those 
chapters  relating  to  the  several  metals. 

5.  Fluxes,  are  used  in  nearly  all  of  the  metallurgical 
processes,  and  their  characteristics  are  determined  by  the 
special  requirements  of  each  case. 

Fluxes  are,  as  the  name  (from  fluo,  to  flow)  indicates,  sub- 
stances which  assist  in  reducing  the  solid  materials  in  the 
smelting  furnace  to  the  liquid  state,  forming  a  compound 
known  as  slag,  or  sometimes  as  cinder. 

It  frequently  happens  that  two  substances,  having  a  pow- 
erful affinity  for  each  other,  will  unite  chemically,  when 
brought  in  contact,  and  fuse  into  a  new  compound  at  a  much 
lower  temperature  than  that  at  which  either  will  melt  alone. 

Silica  fuses  only  at  an  extremely  high  temperature,  if  iso- 
lated, or  if  heated  in  contact  with  bodies  for  which  it  has  no 
affinity ;  but,  if  mixed  with  an  alkali,  as  potash,  soda,  or 
lime,  the  mixture  fuses  readily.  The  two  first-named  alkalies 
are  too  expensive  for  general  use  in  metallurgy ;  but  the  lat- 
ter is  plentifully  distributed,  as  a  carbonate,  and  it  is,  there- 
fore, the  flux  generally  used  in  removing  silica  from  ores,  by 
fusion. 

Borax  similarly  unites  with  oxide  of  iron  to  produce  a 
readily  fusible  glass ;  and  it  is,  therefore,  often  used  by  the 
blacksmith  as  a  flux  when  welding  iron. 

Quartz  sand  is  also  used  by  the  blacksmith  for  precisely 
the  same  purpose.  Being  composed  almost  purely  of  silicic 
acid,  it  forms  a  readily  fusible  silicate  with  the  oxides  of  iron, 
and  it  is  used  wherever  the  mass  of  iron  is  of  considerable  size, 
and  is  capable  of  bearing,  without  injury,  the  high  temperature 
necessary  for  its  fusion. 

Fluor-spar,  a  native  fluoride  of  calcium,  has  been  fre- 
quently and  extensively  used  as  a  flux.  Its  name  was  given 
to  it  in  consequence  of  that  fact.  It  is  a  very  valuable  fluxing 
material,  and  is  used  where  the  expense  of  obtaining  it  does 
not  forbid  its  application.  It  has  special  advantages  arising 
from  the  fact  that  it  is  composed  of  two  elements,  both  of 
which  perform  an  active  and  a  useful  part  in  the  removal  of  the 
non-metallic  constituents  of  ores.  In  the  removal  of  sulphur 


HISTORY  OF  THE  METALS  AND   THEIR  ALLOYS.          13 

• 

and  phosphorus  from  iron,  it  also  possesses  the  great  advan- 
tage  that  the  resulting  compounds  produced  by  its  union  with 
those  elements  are  gaseous,  and  pass  off  up  the  chimney,  in- 
stead of  remaining  either  solid  or  liquid  in  the  furnace  and 
contaminating  the  iron  by  their  contact. 

Since  the  aim,  in  selecting  a  flux,  is  usually  to  form,  with 
the  impurities  to  be  removed,  a  readily  fusible  glass,  such 
materials  are  selected,  in  each  case,  as  are  found,  by  analysis 
or  by  trial,  to  unite  in  those  proportions  which  produce  such 
a  compound. 

The  "slag"  thus  formed  should  usually  be  a  compound 
silicate  of  lime  and  alumina,  as  free  as  possible  from  refractory 
substances,  like  magnesia,  and  from  the  oxides  of  the  metal 
treated. 

The  flux  used,  therefore,  where  an  ore  contains  excess  of 
silex,  is  a  mixture  of  lime  and  alumina — as,  for  example, 
limestone  and  clay. 

Where  the  ore  already  contains  alumina,  limestone  only 
may  be  needed.  In  the  reduction  of  iron  ores,  limestone  is 
very  generally  the  only  material  added  as  a  flux. 

6.  The  Fuels  used  in  engineering  and  metallurgy  are  con- 
sidered very  fully  in  Chapter  IV.,  Part  I.,  of  this  work. 

7.  Mechanical    Processes. — Metallurgy    includes    both 
mechanical  and  chemical  processes.     The  former  consist  in 
crushing  and  washing  ores,  or  the  gangue  with  which  they 
are  associated,   to   render   the  processes  of  reduction  or  of 
separation  more  easy,  complete,  and  economical.  The  "  stone- 
breaker,"  or  "  rock-crusher,"  is  the  form  of  crushing  apparatus 
used  for  breaking  rock  into  pieces  of  fixed  size.     It  often 
consists  of  an  arrangement  of  vibrating  jaw,  J  (Fig.  i),  hung 
from  the  centre,  K,  and  operated  by  a  knee-joint,  G£G,  the 
connecting-rod    of  which,  E,  is  raised    and  depressed  by  a 
crank,  C,  driven  by  a  steam  engine.     A  fly-wheel,  B,  gives 
regularity  of  motion,  and  stores  energy  needed  at  the  instant 
when    the   squeeze   occurs.      Steel    or    cast-iron    faces,   PP, 
receive  the  wear.     The  breadth  of  opening  at  /,  which  de- 
termines the  maximum  size  of  pieces  crushed,  is  adjusted  by 
a  wedge  at  O  Wy  set  by  a  screw  at  N.     The  jaw  is  pulled  back 


14  MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS. 

by  a  spring  R.     Many  modifications  of  this,  the  Blake  crusher, 

are  now  made. 

Stamps  consist  of  heavy  weights  carried  at  the  ends  of 

vertical  rods,  which  are  lifted  either  by  cams  on  a  continuously 

revolving  shaft,  or  by  the  ac- 
tion of  a  steam  piston.  The 
former  are  the  older,  and 
for  many  kinds  of  work  the 
most  effective  style ;  the 
latter  are,  however,  found 
vastly  more  economical  for 
other  cases,  as  in  the  crush- 
ing of  some  of  the  copper- 
bearing  rock  of  the  Lake 
FIG.  I.-STONE-CRUSHER.  Superior  district. 

Washing  machinery  is  largely  used  in  silver  mining  and 
reduction,  and  less  generally  in  working  the  ores  of  the  "  use- 
ful "  metals.  It  takes  many  forms,  according  to  the  kind  of 
work  to  be  done ;  this  is  usually  the  washing  of  earthy  matter 
from  harder  ores  or  the  separation  of  heavy  masses  from 
an  earthy  mass  in  which  it  is  imbedded. 

8.  The  Working  of  Metals,  as  an  art,  antedated,  un- 
questionably, the  very  earliest  historic  periods,  and  introduced 
the  "  age  of  bronze."  The  first  metal-work  was  done  in  gold, 
silver,  copper,  bronze,  brass,  lead,  and  iron,  and  possibly  tin. 
The  East  Indians,  the  Egyptians,  the  early  Greeks,  and  per- 
haps other  nations,  were  familiar  with  methods  of  working 
these  metals  and  alloys,  and  are  said  to  have  been  conversant 
with  a  now  unknown  art  of  hardening  and  tempering  bronze, 
to  give  cutting  edges  on  knives  and  weapons,  which  were 
only  equalled  by  those  of  steel.  Copper  was  much  used 
during  the  Middle  Ages,  and  from  A.D.  iioo  to  150x3  espe- 
cially, for  a  great  variety  of  objects.  Bronze  was  the  most 
common  material  for  works  in  art  among  the  older  nations. 

The  metals  were  worked  both  by  casting  and  by  the 
"  repoussf  method.  The  earliest  castings  were  solid,  and 
the  art  of  economizing  cost  and  weight  by  "  coring  out " 
the  inner  portions  was  one  of  later  introduction.  The  first 


HISTORY  OF  THE  METALS  AND  THEIR  ALLOYS.          I  5 

"  cores  "  in  bronzes  were  of  iron,  and  were  left  in  in  the  cast* 
ing ;  still  later,  removable  clay  and  wax  cores  were  used. 

The  finest  Greek  art-castings  and  those  of  the  Romans, 
and  later  the  Italian  artists,  were  made  by  the  method  called, 
by  French  workers  in,  bronze,  that  "  ct  cire  perdue."  The 
statue  or  other  object  was  first  roughly  modelled  in  clay,  and 
in  size  slightly  less  than  that  proposed  for  the  finished  piece. 
On  this  clay  model  was  laid  a  coating  of  wax,  which  was 
worked  to  exactly  the  intended  finished  size  and  form,  and 
was  frequently  even  given  the  smoothness  of  surface  desired 
in  the  finished  casting ;  this  formed  a  thin  skin  over  the  clay. 
A  clay,  or  earthy,  wash  was  next  applied,  covering  the  wax 
surface,  and  over  this  was  placed  a  thick  and  strong  mass  of 
clay,  worked  on  in  soft  state  and  allowed  to  dry  and  set. 
The  whole  was  then  baked  slowly;  the  wax  melted  and 
flowed  out  from  between  the  two  masses  of  clay,  leaving  a 
space  into  which  molten  bronze  was  finally  poured  to  form 
the  casting.  The  two  parts  of  the  clay  mould  were  secured 
together  by  stays  of  bronze  which  were  built,  or  afterward 
driven,  into  both  parts,  and  thus  connected  them  together. 
When  the  casting  had  cooled,  the  clay  was  torn  away  from 
the  outside  and  removed  from  the  interior  of  the  bronze  ;  the 
surface  was  finished  up  as  required,  and  the  work  was  done. 
The  finest  antique  bronzes  were  thus  made. 

The  hammered,  or  "  repousse"  work  of  the  Greeks  was 
wonderfully  perfect  at  a  date  which  is  supposed  to  have  been 
earlier  than  that  of  their  large  castings.  The  first  efforts  in 
this  direction  were  rude  ;  the  sheet  metal  was  hammered  into 
shape  over  blocks  of  wood,  which  had  been  roughly  given 
the  desired  form.  Later,  a  bed  of  pitch,  or  of  soft  kinds  of 
cement,  was  prepared,  and  the  sheets  hammered  into  form  by 
striking  them  on  the  back  side,  the  bed  yielding  to  the  blow 
and  thus  allowing  the  metal  to  assume  the  desired  shape 
without  being  broken  by  the  hammer  or  by  the  punch  used. 
The  work  was  often  reversed  and  the  final  finish  given  on 
the  front  side.  This  method  produced  some  of  the  largest 
and  the  finest  of  the  ancient  Asiatic  bronzes,  and  fine  work 
in  gold,  silver,  and  copper.  The  Greeks  excelled  in  this 


1 6    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

method  of  metal-working.  In  many  cases,  the  thickness  of 
the  metal  was  reduced  nearly  to  that  of  paper,  without  injury 
to  its  surface.  The  Siris  bronzes  of  about  B.C.  400  are  of  this 
kind. 

Tin  was  probably  worked  into  vess.els  for  domestic  use  by 
the  natives  of  Cornwall  before  the  settlement  of  the  country 
by  the  Romans.  Lead  was  used  throughout  Europe,  in  the 
mediaeval  period,  in  sheets  for  roof-coverings,  and  cast  into 
objects  of  complicated  form.  Specimens  remain  of  the 
former,  exhibiting  its  great  durability  when  exposed  to  the 
weather. 

Like  the  modern  Chinese  and  Japanese  artists,  the  ancient 
workers  in  metal  used  gold  and  silver  to  adorn  and  give 
relief  to  their  castings  in  bronze.  Mirrors,  of  fine  surface 
and  thus  ornamented,  are  common  among  collections  of  the 
products  of  Greek  art.  The  bronzes  of  the  Italian  artists  of 
the  Middle  Ages  are  remarkable  for  their  beauty  as  art  work 
in  metal,  as  well  as  for  their  beauty  of  design  ;  even  their 
work  in  iron  is  famous  for  its  unexcelled  beauty  and  the  skill 
exhibited  in  forging  it.  Modern  work  has  not  equalled  that 
of  the  Middle  Ages,  or  even  that  of  the  early  Greeks. 

9.  Metal  is  the  name  applied  to  above  fifty  of  the  chem- 
ical elements.     The   larger  number  of   the    metals   are   but 
little  known,  and  many  are  found  in  such  extremely  minute 
quantities,  that  we  are  not  well  acquainted  with  either  their 
chemical  or  their  physical  characteristics.     Some  approach 
the  non-metallic  elements  so  nearly  in  their  properties,  that 
they  are  placed,  sometimes  in  the  one  class,  and  sometimes  in 
the  other.     Very  few  of  the  metals  are  well  fitted  for  use  in 
construction ;  but,   fortunately,  those  few  are  comparatively 
widely  distributed,  and  are  readily  reduced  from  their  oxides 
or  sulphides,  in  which  states  of  combination  they  are  almost 
invariably  found  in  nature. 

10.  The  "  Useful  Metals  "  are  iron — in  its  various  forms 
of  cast  iron,  malleable  or  wrought  iron,  and  steel — copper, 
lead,  tin,  zinc,  antimony,  bismuth  and  nickel,  and  occasionally 
aluminium  and  rarer  metals  are  used  for  similar  purposes. 

From  this  list  of  metals,  and  from  their  alloys,  the  engi- 


HISTORY  OF  THE  METALS  AND  THEIR  ALLOYS.          IJ 

neer  can  almost  invariably  obtain  precisely  the  quality  of 
material  which  he  requires  in  construction.  He  finds  here 
substances  that  exceed  the  stones  in  strength,  in  durability 
under  the  ordinary  conditions  of  mechanical  wear,  and  in  the 
readiness  and  firmness  with  which  they  maybe  united.  They 
are  superior  to  timber  of  the  best  varieties  in  strength,  hard- 
ness, elasticity  and  resilience,  and  have,  in  addition,  the  im- 
portant advantages,  that  they  may  be  given  any  desired  form 
without  sacrificing  strength,  and  may  be  united  readily  and 
firmly  to  resist  any  kind  of  stress. 

By  proper  selection  or  combination,  the  engineer  may 
secure  any  desired  strength,  from  that  of  lead,  at  the  lower, 
to  the  immense  tenacity  of  tempered  steel,  at  the  upper 
limit.  He  obtains  any  degree  of  hardness,  or  fusibility,  and 
almost  any  desired  immunity  from  injury  by  natural  destroy- 
ing agencies.  Elasticity,  toughness,  density,  resonance,  and 
varying  shades  of  color,  smoothness,  or  lustre,  may  also  be 
secured. 

11.  The  Laws  Governing  Distribution  of  the  Ores  of 
the  metats  are  comprehended  in  the  science  of  geology.    The 
detection  of  their  presence  in  any  locality,  and  bringing  them 
to  the  surface  of  the  ground,  free   from  the  foreign  earthy 
substances  which  accompany  them,  is  the  work  of  the  min- 
ing engineer,  and  of  the  miner.     The  "reduction"   of  the 
metals  from  ores,  by  chemical  and  mechanical  processes,  con- 
stitutes the  business  of  the  metallurgist.     The  engineer  takes 
the  metals  as  they  are  brought  into  the  market,  and  makes 
use  of  them  in  the  construction  of  permanent  or  movable 
structures. 

12.  The  Requirements  of  the   Engineer  include  some 
acquaintance  with  the  general  principles,  and  with  the  ex- 
perimental knowledge,  which  are  to  be  obtained  by  the  study 
of  geology;  of  mining,  and  of  metallurgy,  to  aid  him  in  select- 
ing the  metals  used  in  his  constructions ;  since  their  quali- 
ties cannot  always  be  determined  by  simple  inspection,  and 
it  is  not  always  possible  to  subject  them  to  such  tests  as  he 
may  consider  desirable  before  purchasing.     In  such  cases,  a 
knowledge  of  the  localities  whence  the  ores  were  obtained, 


1 8    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

familiarity  with  the  processes  of  manufacture,  and  with  the 
nature  of  the  materials  employed  by  the  metallurgist,  coupled 
with  a  knowledge  of  the  effects  of  various  foreign  substances 
upon  the  quality  of  the  metal,  may  enable  the  engineer  to 
judge  with  some  accuracy  what  metal  will  best  suit  his  pur- 
poses, and  what  will  be  likely  to  prove  valueless.  He  is  also 
thus  enabled  to  judge,  should  the  purchased  material  prove 
defective,  where  the  defect  in  quality  originated,  and  to  place 
the  responsibility  where  it  belongs. 

The  student  will  seek  this  knowledge  in  special  works  on 
geology  and  metallurgy.  But  brief  reference  can  be  made  to 
these  subjects  here. 

All  the  metals  possess,  as  a  whole,  a  number  of  properties 
which  define  the  class,  although  few  of  these  properties  are 
common  to  all.  The  metals  all  unite  chemically  with  oxygen 
to  form  basic  oxides,  and  some  of  them  take  higher  proportions 
of  oxygen,  forming  acids.  All  metals  are  capable  of  similarly 
uniting  with  chlorine.  All  are  capable  of  fusion  and  lique- 
faction at  certain  temperatures,  fixed  for  each,  which  are 
usually  high.  Mercury,  however,  is  liquid  at  ordinary  tem- 
peratures. The  metals  are  also  capable  of  vaporization,  and 
their  vapors  have  some  physical  characteristics  quite  different 
from  those  of  the  solid  metal.  Thus,  silver,  white  when  solid 
or  liquid,  becomes  blue  as  a  vapor;  mercury  vapor  is  color- 
less, potassium  is  green.  All  are  opaque,  except  in  exceed- 
ingly thin  films,  when  some  become  apparently  translucent. 
Gold  transmits  green  light,  mercury  blue,  and  silver  remains 
opaque  in  the  thinnest  leaf  yet  made. 

13.  The  Special  Qualities  of  the  Useful  Metals  which 
give  them  their  importance  as  materials  of  construction  are : 
their  strength,  hardness,  density,  ductility,  malleability,  fusibil- 
ity, lustre,  and  conductivity. 

Strength,  or  the  resistance  offered  to  distortion  and  fract- 
ure, is  their  most  valuable  quality.  The  strength  of  metals 
and  alloys  in  general  use  has  been  very  carefully  determined 
by  experiment,  and  will  be  given  hereafter. 

Of  the  metals  in  our  list,  lead  is  the  least  tenacious,  and 
steel  is  the  strongest. 


HISTORY  OF  THE  METALS  AND  THEIR  ALLOYS.          19 

14.  The  Non-Ferrous  Metals,  which  are  to-day  of  com- 
paratively little  importance  to  the  engineer  in  the  construction 
of  machines  or  of  structures,  and  which  have  been  so  generally 
superseded  by  iron  and  steel  in  every  department  of  art,  were, 
in  earlier  times,  in  some  cases,  as  copper,  tin,  lead,  the  most 
common  materials  of  construction.    The  three  just  mentioned 
were  known  in  prehistoric  times,  and  the  Greeks  were  also 
familiar  with  mercury,  as  well  as  with  iron.     Valentinus  dis- 
covered and  described  antimony  in    the   I5th  century,  and 
bismuth  and  zinc  became  known  at  about  the  same  time  or  a 
little  later.     Brande  discovered  arsenic  and  cobalt  about  the 
middle  of  the   1 8th  century,  and  Ward  discovered  cobalt.* 
Cronstedt  discovered  nickel  and  Scheele  manganese  in  1774, 
and  tungsten  was  prepared  in  1783  by  the  brothers  D'Elhu- 
jart.     Palladium,  rhodium,  indium  and  osmium  were  isolated 
and  described  by  Wollaston  and  others  in  1803.     The  alkaline 
earths,  recognized  as  oxides  by  Davy  in   1807-8,  were  soon 
after  deoxidized,  and  potassium  and  sodium  became  known. 
Aluminium  and  magnesium  were  separated  in  1828  and  1829, 
respectively  by  Wohler   and   by  Bussy,  and    cadmium  had 
already  been  discovered  by  Stromeyer  in   1818.     The  rarer 
and   more    unfamiliar   metallic    elements  were    found    later. 
The  properties  of  these  metals  have  been  referred  to   in   a 
general  way  in  an  abridged  account  of  them  given  in  Part  II. 
of  this  work.     A  more  detailed  account  of  those  used  in  con- 
struction will  occupy  the  greater  part  of  this  volume.     The 
following  is  a  resume  of  the  general  characteristics  of  these 
metals. 

15.  The  Relative  Tenacities  are  approximately  as  below, 
lead  being  taken  as  the  standard. 

TABLE    II. 

RELATIVE   TENACITIES   OF  METALS. 


Lead i.o 

Tin 1.3 

Zinc 2.0 

Worked  copper 12  to  20 


Cast  iron 7  to    12 

Wrought  iron 20  to    40 

Steel 40  to  loo 


*  Encyclopaedia  Britannica,  1883,  art.  Metals. 


20  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

No  two  pieces  of  metal,  even  nominally  of  the  same  grade, 
have  precisely  the  same  strength.  The  figures  can  therefore 
only  represent  approximate  ratios,  as  every  variation  of 
purity,  structure,  or  even  of  temperature,  is  found  to  affect 
their  strength. 

Cast  metal  is  usually  weaker  than  the  same  metal  after 
having  passed  through  the  rolls  or  under  the  hammer ;  those 
which  can  be  drawn  into  wire  are  still  more  considerably 
strengthened  by  that  process.  Metals  are  stronger  at  ordi- 
nary temperatures  than  when  highly  heated,  and  "  annealing  " 
is  found  to  reduce  the  strength  of  iron  and  steel,  although 
frequently  increasing  their  ductility,  and  produces  an  op- 
posite effect  on  copper  and  its  alloys.  "  Hardening,"  pro- 
duces the  contrary  effect.  The  presence  of  impurities  and 
the  formation  of  alloys  produce  changes  of  strength,  some- 
times increasing,  sometimes  diminishing  it. 

Copper  alloyed  with  tin  or  zinc,  in  certain  proportions,  is 
strengthened ;  and  the  addition  of  a  small  percentage  of 
phosphorus  to  the  alloy  has  a  marked  effect  in  increasing  its 
tenacity  and  ductility. 

16.  Hardness  varies  in  the  metals  as  considerably  as  their 
tenacity,  and,  like  the  latter  quality,  is  greatly  influenced  in 
the  same  metal  by  very  slight  changes,  either  physical  or 
chemical. 

Thus  metals  are  hardened  by  cold  hammering  and  softened 
by  sudden  change  of  temperature.  The  addition  of  scarcely 
more  than  a  trace  of  impurity  often  produces  a  marked 
change  in  the  degree  of  hardness  of  metals. 

The  scale  of  hardness,  according  to  Gollner,*  is  as  follows: 


Soft  lead. 
Tin.. 


i 

2 

Hard  lead 3 

Copper 4-5 

Alloy  for  bearings 

(C.,85;  T.,  io;Z.,  5).  6 

Soft  cast  iron 7 

Wrought  iron 8 


Cast  iron 10-11 

Mild  steel 12-13 

Tool     "    blue 14 

"        "    violet 15 

"         "    straw 16 

Hard  bearings 

(C,  83;  Z.,  17) 17 

Very  hard  steel 18 


*  Tech.  Blaetter ;  London  Engineering,  June  I,  1883,  p.  519. 


QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.       21 

The  hardness  of   metals,  as   determined   by   Dumas,    is 
exhibited  in  the  following  table  of  their  order. 


TABLE  III. 


HARDNESS   OF  THE  METALS. 


Titanium 
Manganese 

Scratch  steel. 

RhodTuT    1   Scratch  Slass 

Platinum 

Nickel 

Palladium 

Cobalt 

Copper 

Iron 

-  Scratched  by 

Gold 
Silver 
Tellurium 

Scratched  by 
'    Calc  Spar. 

Antimony 
Zinc 

Scratched  by 

Bismuth 

.L,eaa 

the  nail. 

Cadmium 
Tin                 J 

Potassium 
Sodium 

Soft  as  wax. 

Mercury,           Liquid. 

17.  Conductivity,  or  their  power  of  transmitting  molecu- 
lar vibrations  of  either  heat  or  electricity,  is  another  property 
of  the  metals,  upon  which  is  founded  many  useful  applications, 

Of  the  "  useful "  metals,  copper  has  by  far  the  highest 
conductivity,  and  is  only  second  in  this  respect  to  gold  and 
silver,  the  best  known  conductors.  Its  conductivity  is  greatly 
reduced  by  the  presence  of  foreign  substances. 

The  powers  of  conduction  for  heat  and  electricity  seem 
to  have  very  similar  relative  values.  Conductivity  is  reduced 
by  increase  of  temperature  and  by  presence  of  impurities. 

The  following  table  of  relative  conductivities  was  deter- 
mined by  the  experiments  of  Despretz,  and  very  closely  con- 
firmed by  Forbes. 

TABLE  IV. 


RELATIVE   THERMAL   CONDUCTIVITIES  OF   METALS. 


Gold 1,000 

Silver 973 

Copper 878 

Iron 374 


Zinc 360 

Tin... 304 

Lead 180 

Marble 25 


The  electric  conductivities  obtained  by  Becquerel,  and  the 


22    MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS. 


thermal  conductivities  given  by  Wiedmann  and  Franz,  are  as 
below :  * 

TABLE    IVtf. 


CONDUCTIVITIES    OF   METALS. 


ELECTRIC. 

THERMAL. 

In  Vacuo. 

In  Air. 

Silver    .  .                                       

T.OOO 

I,OOO 

'748 
548 

240 

154 

84 

79 

T,OOO 

'736 
532 
236 
145 
840 

85 

18 

Copper.  . 

,ppci                            .    ' 

commercial                                   .  . 

915 
649 

140 
79-3 

82.7 

Gold  

Brass 

Tin      .                                    .... 

Platinum  

Lead 

Bismuth 

The  resistance  to  the  voltaic  current  has  been  found  by 
Mr.  K.  H  edges  f  as  follows,  wire  and  foil  being  used,  and 
strength  of  the  current  so  adjusted  that  on  increasing  it  20 
per  cent,  the  metal  would  fuse.  The  experiments  continued 
24  hours  and  the  temperature  was  69°  F.  (21°  C.) 

TABLE  V. 

RESISTANCES    OF    METALS   TO    ELECTRIC    CURRENTS. 


METAL. 

Before  Heating. 

Change  in 
24  Hours. 

I.  Commercial  tin, 
2.   Lead,  soft  

wire  

0.815   Ohms. 
0.835 
o.Sio 
0.860 
0.800 
0.835 
0.820 

—  0.003 
—  0.005 
+  o.ooo 

+  0.000 

—  0.160 
+  o  ooo 
+  0.0008 

3.  Copper,  soft.  .  . 

4.   Tin-foil,  pure.. 

5.  Tin  and  lead.  .  . 

6.  Aluminium  ("A 
7.  Aluminium  and 

ilbo  ")  alloy    foil 

tin  

RESISTANCES  AS  MEASURED. 


*  Part  II.,  p.  8,  §  10. 

f  Brit.  Assoc.  Reports,  1883,  Sec.  G. 


QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.        2$ 


Commercial  copper  (Rio  Tinto),  has  been  found  to  have, 
in  some  cases,  but  one-seventh  the  conductivity  of  pure 
copper. 

Conductivity  is  reduced  by  increase  of  temperature,  ac- 
cording to  Forbes,  and  at  rates  varying  with  the  character  of 
the  metal. 

M.  Benoit  has  measured  the  electrical  resistance  of  various 
metals  at  temperatures  from  o°  to  860°  C.  The  mean  of  the 
figures  obtained  is  given  in  the  following  table,  the  second 
column  giving  the  resistance  in  ohms  of  a  wire  39.37  inches 
(i  metre)  long,  and  having  a  cross  section  of  0.03  inch  (0.2 
sq.  cm.),  and  column  three  the  same  quantity  in  Siemens 
units.  Column  four  gives  the  conductivity  compared  with 
silver : 

TABLE  Va. 


METAL. 

OHMS. 

SIEMENS. 

Silver    A  

.OI54 

0161 

IOO 

Copper   A 

OI7I 

OI7Q 

Silver   A  (i)    

.oicn 

O2OI 

80 

Gold,  A  

.O2I7 

O227 

71 

Aluminium    A 

O^OQ 

OQ2J. 

4Q    7 

Magnesium    H   

.042^ 

O44^ 

06   4 

.(x6^ 

O^QI 

27.  *, 

Zinc    H 

OCQ  1 

O62I 

2C    Q 

Cadmium,  H  

.068=; 

O7l6 

*P*V 

22  «; 

Brass  A.  (2)  

.0601 

•  O72T 

22.  1 

Steel    A 

IOQQ 

II4Q 

14 

Tin                      

1161 

1214 

j<i    <i 

Aluminium  bronze,  A.  (3)  

nSo 

•  124^ 

fflj 

Iron    A 

1216 

1272 

12    7 

Palladium   A       .  .        ... 

.1184 

1147 

II    I 

Platinum,  A    

.  1^75 

.1647 

Q   77 

Thallium   

.1831 

.  IQI4 

8.41 

Lead 

.  1085 

.207^ 

77  60 

German  silver,  A   (4)  

*y"J 
.2654 

':> 

•  2775 

5.8o 

.9564 

I.OOOO 

1.61 

A,  annealed;    H.  hardened;  (i)  silver  .75;  (2)  copper  64.2,  zinc  33.1,  lead  0.4,  tin  0.4; 
(5)  copper  90,  aluminium  10 ;  (4)  copper  50,  nickel  25,  zinc  25. 

These  results,  are  all  taken  at  o°  C.,  and  agree  closely  with 
those  obtained  by  other  observers.  The  resistance  increases 
regularly  for  all  metals  up  to  their  points  of  fusion.  This 


24  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

increase,  however,  differs  for  different  metals.  Tin,  thallium, 
cadmium,  zinc,  lead,  are  found  to  vary  similarly;  at  200°  to 
230°  their  resistance  has  doubled.  The  resistance  of  iron  and 
steel  doubles  at  180°,  quadruples  at  430°,  and  at  860°  is  about 
nine  times  that  at  o°.  Palladium  and  platinum  increase  much 
less,  their  resistance  becoming  twice  that  at  o°  C,  at  400°  to 
450°.  Gold,  copper,  and  silver  form  an  intermediate  group. 
In  general  conductibility  decreases  more  rapidly  the  lower  its 
point  of  fusion.  Iron  and  steel  are  exceptions  to  this  rule. 
In  alloys  the  variation  is  less  than  in  their  constituents,  and 
this  is  especially  the  case  with  German  silver. 

The  thermal  conductivity  of  brass  was  found  by  Isher- 
wood  to  be  556.8  thermal  units  (British)  per  hour  per  square 
foot  and  per  i°  Fahr.,  and  to  vary  at  the  difference  of  tem- 
perature. 

Silicon-bronze  may  be  given  a  conductivity  but  little  less 
than  that  of  copper,  but  its  tenacity  then  diminishes  con- 
siderably; that  having  95  per  cent,  the  conductivity  of 
copper,  has  but  one  half  the  strength  of  that  of  which  the 
conductivity  is  25  per  cent. 

18.  The  Lustre  of  these  metals  is  measured  by  their 
power  of  reflecting  light.  Thus,  according  to  Jamin,  silver 
may  reflect  0.9  of  the  light  sent  between  surfaces  of  mirrors 
made  of  that  metal ;  after  ten  normal  reflections  it  yields 
from  0.24  to  0.48,  the  former  figure  being  that  for  violet,  and 
the  latter  for  red  light.  The  figures  for  speculum  metal  are 
0.6  to  0.7,  0.006  and  0.035  ;  those  for  steel,  0.6,  0.006,  and 
0.007. 

Estimating  weights  of  metal  in  various  forms  as  used  by 
the  engineer  is  a  simple  operation.  Thus  :  if 

d    —  diameter  of  a  circular  section,  or  the  minor  diameter 

of  an  ellipse ; 

d'  =  major  diameter  of  ellipse  ; 
/     =  length  of  piece,  section  uniform  ; 
b    =  breadth ; 
k    —  a  constant ; 
W '—  total  weight. 


QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.       2$ 

The  weight  of  any  piece  of  uniform  section  is 

W '=  kd*l  for  cylindrical  bars  ; 
=  kdd'l  "    elliptical  sections ; 
=  kbdl  "    rectangular  sections. 

The  values  of  k  when  /  is  in  feet,  other  dimensions  in 
inches  and  Win  pounds,  are 

VALUES   OF  k  IN 


W  '=  kdd'l. 

W=  kbdl. 

2.906 

•j    700 

Iron    wrought 

2  618 

3-7-J-3 

3  888 

4QCQ 

Steel,  soft  

2.670 

1.  ,  J.OO 

For  pipes,  W=  k(d?  —  df)  when  d^d2  represent  the  inner 
and  outside  diameters  in  inches. 

To  obtain  weights  in  kilogrammes  when  measures  are  in 
centimeters,  multiply  the  above  by  0.00241. 

The  "  metallic  lustre  "  is  a  property  of  the  metals  almost 
peculiar  to  them,  and  constitutes  one  of  their  marked  charac- 
teristics. 

Polished  steel,  and  an  alloy  of  copper  and  tin  known  as 
speculum  metal,  burnished  copper  and  aluminium,  as  well  as 
the  precious  metals,  gold  and  silver,  exhibit  this  beautiful 
and  peculiar  lustre  very  strikingly. 

Tin,  lead,  and  zinc,  are  lustrous,  but  they  are  not  capable 
of  taking  a  sufficiently  high  polish  to  exhibit  this  quality  in 
such  a  degree  as  the  metals  first  named. 

19.  The  Specific  Gravities  of  the  commercial  metals  are' 
as  follows : 

THE  DENSITIES  OF  PURE  METALS  according  to  Fownes,* 
are 


*  Chemistry,  loth  eel.,  p.  297. 


26  MATERIALS  OF  ENGINEERING— NON'-FERRO US  METALS. 


TABLE  VI. 


SPECIFIC    GRAVITIES    OF    PURE    METALS. 


(Water  at  60°  F.  (15-5  C.)  =  i.) 


Platinum 21 . 50 

Indium 21.15 

Gold 19-50 

Tungsten 17 . 60 

Mercury  ....    J3  •  59 

Palladium u .  80 

Lead *i-45 

Silver 10.50 

Bismuth 9-9° 

Copper 8 . 96 

Nickel 8.80 

Cadmium 8 . 70 

Molybdenum 8 . 63 


Cobalt 8.54 

Manganese 8.00 

Iron   7-79 

Tin 7.29 

Zinc 7. 10 

Antimony 6 . 80 

Tellurium 6.11 

Arsenic 5.88 

Aluminium 2.67 

Magnesium 1.75 

Sodium 0.97 

Potassium o. 87 

Lithium o. 59 


For  the  purposes  of  the  engineer,  the  densities  and  the 
weights  per  unit  of  volume  of  commercial  materials  are  the 
data  desired.  The  following  table  gives  such  a  set  of  figures. 
As  is  seen  by  comparing  the  tables,  authorities  differ  some- 
what in  these  figures. 


TABLE  VII. 

WEIGHTS   AND    DENSITIES    OF    COMMERCIAL   METALS. 


NAME. 

S.  G. 

LBS.   IN 
CU.    FT. 

KILOG'S 

IN   CU.    M. 

2.56 

1  60 

2,560 

sheet     

2.67 

167 

2,670 

Antimony    cast                                

6.7 

418 

6,700 

Bismuth,        "     -  

9.8 

614 

9,800 

Brass  *  cast                                                         .    .  . 

8.4 

525 

8,400 

"       sheet      .        .                        

8.5 

S32 

8,500 

<4       wire 

8.54 

eo-3 

8,540 

Bronze  *  (ordinary)     .                  .                

8.4 

Ci24 

8,400 

Copper,*  bolts   

8.85 

548 

8,850 

"         cast 

8  60 

c-37 

8,600 

"         sheet                                           

8.88 

54Q 

8,800 

'  '         wire  

8.88 

550 

8,800 

Gold,  hammered      .                        .          

10   4 

I.2O5 

10,400 

'  '     standard  

17.65 

I,TO3 

17,650 

Gun  metal  (bronze)  .  . 

S.I*'* 

510 

8,153 

QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.       2J 
TABLE  VII.— Continued. 


NAME. 

S.  G. 

LBS.  IN 
CU.  FT. 

KILOG'S 

IN   CU.  M. 

Iron  cast    from                              .  .                . 

6    Q55 

4<iq 

6  Q55 

"     to     ..                      

7.205 

4c6 

7  205 

7.121; 

445 

7,125 

wrought,  from                      ...        . 

7   ^60 

471 

7  560 

"         to              

7.800 

488 

7,8OO 

4  '         average 

7   680 

48O 

7  680 

Lead    cast                 .              ... 

II  .  1^2 

7IO 

II  152 

«      sheet     

11.4 

712 

IT,4OO 

Mercury    fluid 

ii  6 

8.18 

11  OOO 

•  '         solid                                   .                      « 

1^  .6^2 

Q77 

15  6l2 

Nickel   cast          

7.807 

488 

7  807 

Pewter  

I  I.  600 

725 

II,  600 

Platinum,  mass 

IQ.  550 

I  2IQ 

I9,5OO 

"         sheet      

20.  3^7 

1,271 

2O  117 

Silver,  mass  

10.  5 

655 

10,500 

"        standard         • 

IO   514 

IO,  5  14. 

Steel   hard              

7  82 

4Q6 

7,820 

"     soft  

7  834 

49  1 

7,  8  14 

Tin,*  cast 

7.-1 

4^6 

7  ^OO 

Type  metal  cast    ...      .        .              

10.450 

6ti 

10,4^0 

Zinc,*  cast  

7.O1 

43Q 

7.O1O 

"       sheet   . 

7    2Q 

4c6 

7.2QO 

20.  Ductility  and  Malleability  are  properties  of  the  met- 
als scarcely  less  important  to  the  engineer  than  that  of 
tenacity.  The  ductility  of  a  metal  or  an  alloy  is  its  capacity 
for  being  drawn  out  into  wire,  by  being  pulled  through  holes 
in  the  wire-drawers'  plates,  each  hole  being  slightly  smaller 
than  the  preceding,  until  the  wire  reaches  a  limit  of  fineness 
which  is  determined  by  the  degree  of  its  ductility,  and,  as 
well,  by  the  skill  of  the  workman. 

Great  tenacity,  in  proportion  to  the  degree  of  hardness, 
or  high  tenacity,  a  low  elastic  limit  and  a  certain  viscosity, 
is  the  combination  of  qualities  required  to  insure  dura- 
bility. 

Gold  has  been  drawn  until  the  wire  measured  but  ^Vo 
inch  in  diameter,  and  silver  and  platinum  are  nearly  as  duc- 
tile. Iron  and  copper  are  the  most  ductile  of  the  common 
metals. 


*  See  text  later. 


28   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

The  malleability  of  a  metal,  or  the  power  which  it  pos- 
sesses of  being  rolled  into  sheets  without  tearing  or  breaking, 
is  determined  by  its  relative  tenacity  and  softness. 

The  malleability  of  the  non-ferrous  metals  is  determined 
by  their  plasticity  simply,  and  this  quality  is  observable  in 
all  metals  having  no  defined  elastic  limit.  It  is  also  often 
determined  to  some  extent  by  the  physical  condition  of  the 
metal ;  thus  zinc,  brittle  in  the  ingot,  is  malleable  at  the 
boiling  temperature  of  water,  and,  if  worked  at  that  tempera- 
ture, becomes  permanently  malleable  in  the  sheet  or  the  bar. 
Hardening  and  tempering  are  operations  which  can  be  per- 
formed on  many  metals  with  the  effect  of  modifying  their 
malleability  and  other  properties  ;  but  while  sudden  cooling 
from  high  temperature  hardens  steel,  it  softens  copper  and 
the  bronzes  and  brasses.  Ductility,  being  dependent  upon 
tenacity  largely,  is  not  as  generally  observed  as  malleability. 

Gold  is  the  most  malleable  of  all  metals,  and  has  been 
beaten  into  sheets  of  which  it  would  require  300,000  to  make 
up  a  thickness  of  one  inch.  ' 

Wrought  iron  of  good  quality,  and  the  softer  grades  of 
steel,  are  very  malleable ;  the  former  has  been  rolled  to  less 
than  YjJj-j-  of  an  inch  (0.00254  centimetre)  thickness.  Cast 
iron  and  hard  steels  are  neither  malleable  nor  ductile. 

Copper  is  very  malleable,  as  well  as  ductile,  if  kept  soft 
by  frequent  annealing ;  tin  possesses  this  property,  also  ;  and 
zinc,  although  quite  brittle  when  cold,  becomes  malleable 
at  a  temperature  somewhat  exceeding  the  boiling  point  of 
water  ;  its  temperature  being  still  further  elevated,  it  again 
becomes  brittle,  so  much  so  that  it  may  be  powdered  in  a 
mortar.  Some  of  the  copper-tin  alloys  exhibit  the  same 
peculiarity. 

21.  Odor  and  Taste  characterize  many  metals.  Brass,  for 
example,  possesses  a  very  marked  taste  and  perceptible  odor 
when  applied  to  the  tongue  and  when  rubbed.  These  qual- 
ities may  indicate  solubility  and  volatility,  but  no  direct  ex- 
periment  has  revealed  their  precise  nature.  Many  of  the 
lighter  metals  are  quite  volatile  at  moderately  high  tempera- 
ture. 


QUALITIES  OF  THE  METALS  AXD   THEIR  ALLOYS.       29 

Lead  can  be  rolled   into  quite  thin  sheets,  but  it  is  less 
malleable  than  either  copper,  tin,  or  the  precious  metals. 
The  following  is  a  table  of  the  relative  ductility  of  metals : 

TABLE  VIII. 

ORDER   OF   DUCTILITY    OF    METALS. 

1.  Gold,  4.   Iron,  7.   Zinc, 

2.  Silver,  5.   Copper,  8.   Tin, 

3.  Platinum,  6.  Aluminium,  9.   Lead. 

In  the  following  list,  the  metals  named  are  placed  in  the 
order  of  their  malleability. 

TABLE  IX. 


ORDER   OF   MALLEABILITY   OF    METALS. 


1.  Gold, 

2.  Silver, 

3.  Copper, 


4.  Tin, 

5.  Platinum, 

6.  Lead, 


7.  Zinc, 

8.  Iron, 

9.  Nickel. 


Prechtl  gives  the  following  as  the  order  in  which  the  metals 
stand  in  this  respect  :* 

TABLE   IXa. 


MALLEABILITY. 


DUCTILITY. 


Hammered. 

Rolled. 

Wire-drawn. 

i.  Lead, 

Gold, 

Platinum, 

2.   Tin, 

Silver, 

Silver, 

3-   Gold, 

Copper, 

Iron, 

4.   Zinc, 
5.   Silver, 

Tin, 
Lead, 

Copper, 
Gold, 

6.  Copper, 
7.   Platinum, 

Zinc, 
Platinum, 

Zinc, 
Tin, 

8.   Iron. 

Iron. 

Lead. 

Authorities  differ,  however,  in  their  statements  in  regard  to 
the  order  of  the  metals  in  these  respects,  and  the  preceding 
figures  as  given  in  tables  are  often  quoted  from  Regnault.f 


*  Encyclopaedia  Britannica. 


f  Regnault's  Chemistry. 


30  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

22.  The  following  table  of  the  principal  metals  and  their 
properties  is  extracted  from  Watts  :* 


TABLE  X. 

CHARACTERISTICS    OF   METALS. 


NAME. 

°l 

£  o 

NAME    OF 
DISCOVERER. 

S.   G. 

SP.  HEAT. 

MELTING 
PO^NT. 

CONDUC- 
TIVITY. 

^ 

0 

Water  =  i. 

Ther- 
mal. 

Elect. 

Platinum  .  .  . 
Iridium  .... 
Gold  

1741 
1803 

Wood 

21.5 
21.15 
19.26 
15.60 
II.80 

11-33 
10.57 
9.80 
8.94 

8.82 

8.02 

7.84 
7-30 
7.13 
6.72 

2.56 

1.74 

0.0324 
0.0326 
0.0324 
0.0319 
0.0593 
0.0314 
0.0570 
0.0308 
0.0952 
O.IO86 
O.I2I7 
O.II38 
0.0562 
0.0955 
0.0508 
0.2143 
0.2499 

8.4 

18. 

1200°  C.  (?) 

—  39°  C.  .  . 

53-2 

78. 

Mercury.  .  .  . 

Palladium  .  . 
Lead  

1803 

Wollaston 

6-3 

8-5 

IOO 

i.S 
73-5 

18.4 

8-3 

IOO 
1.2 

99-9 
13-1 

332°  C... 
1000°  C.  .. 
270°  C..  . 

1200°  C.  (?) 

Silver  

Bismuth 

Copper.  . 

Nickel 

1751 
1774 

Cronstedt  
Gahn  ;  Scheele. 

Manganese.  . 
Iron  

. 
2000°  C.  (?) 

11.9 
14-5 

16.8 
12.4 
29. 
4.6 
56.1 
41.2 

Tin     .  . 

Zinc  

4<j<j°   C 

Antimony  .  . 

4^0°   C.  . 

Aluminium..  1828 
Magnesium  .  Ji82g 

Wohler 

Bussey 

j.^^c  C. 

23.  Crystallization  is  always  observed  in  metal  when  de- 
posited from  solution  or  when  solidifying  from  fusion  when  the 
conditions  are  favorable.  Gold,  silver,  copper,  antimony  and 
bismuth,  and  many  alloys,  as  those  of  copper  and  of  iron,  are 
found  in  crystalline  form  in  nature.  Deposition  by  the  vol- 
taic current  often  produces  very  large  and  perfect  crystals. 
Lead  is  precipitated  from  solutions  in  beautiful  crystalline 
forms  when  displaced  by  zinc.  Iron  forms  well-defined  crys- 
tals when  kept  heated  at  nearly  the  temperature  of  fusion  for 
a  considerable  time,  and  is  supposed  by  some  authorities 
to  take  on  the  cubic  form  when  exposed  to  severe  and 
long-continued  jarring.  This  tendency  to  crystallization  is 


*  Dictionary  of  Chemistry  ;  Lond.,  1868  ;  vol.  iii,  ;  p.  936. 


QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.       31 


increased  by  the  presence  of  manganese  or  of  phosphorus. 
Zinc,  in  the  ingot,  is  often  very  distinctly  crystalline. 

The  precious  metals,  aluminium,  cobalt,  copper,  iron,  lead 
and  nickel  are  so  nearly  amorphous,  or  if  crystalline  in  struct- 
ure in  their  ordinary  state,  have  such  small  and  uniform  crys- 
tals that  they  may  be  considered  compact  and  homogeneous. 
Antimony,  bismuth,  manganese,  and  zinc,  and  some  of  their 
alloys  often  exhibit  distinct  crystallization,  which  may  also 
be  produced  in  all  metals  by  prolonged  heating  or  slow  cool- 
ing, and,  as  supposed  by  some  observers,  by  long-continued 
vibration  or  jarring. 

24.  Specific  Heats. — The  effect  of  heat  upon  metallic  sub- 
stances in  the  production  of  changes  of  volume  and  of  tem- 
perature varies  considerably. 

The  Specific  Heats  of  a  number  are  given  in  Table  XI. ; 
they  measure  in  thermal  units  the  quantity  of  heat  required 
to  change  the  temperature  of  a  pound  or  a  kilogramme  of  the 
metal  one  degree. 

TABLE  XL 

SPECIFIC    HEATS    OF   METALS. 


SPECIFIC 
HEAT. 


AUTHORITY. 


\Vrought  iron.                      . 

.IIl8 

Regnault. 

"             32  —  212  F  

Dulong  &  Petit. 

11             -12  —  ^O2  F 

.II^O 

"             T2  —  =i72  F. 

.1218 

M 

32  —  662  F    

.1255 

« 

.1298 

Regnault. 

Steel  soft     .           .  .                       

.1165 

« 

•  IJ75 

(t 

Cooper 

.00515 

tt 

"rr*-1  
32  —  212  F                                

-OQ27 

Dulong  &  Petit. 

«      32—572  F  . 

.  IOI3 

CobaU                                                     .  .     .  . 

.I06o6 

Regnault. 

**      carburetted                      

.11714 

tt 

Nickel    

.1086 

tt 

"      carburetted                             

.niq 

tt 

Tin,  English     

jy 

.05695 

tl 

.  05623 

tt 

Zinc                         

.09555 

tt 

"       32  —  212  F  

.0927 

Dulong  &  Petit. 

"       32  —  572  F  .  . 

.1015 

32    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE  XI.— Continued. 


SPECIFIC 
HEAT. 

AUTHORITY. 

OQ^Q 

Regnault. 

Lead             

.0^14 

«< 

072-1  "^ 

(f 

*           32  —  212  F 

OT7C 

Dulong  &  Petit. 

f         at      572  F  .  . 

034.34 

Pouillet. 

1            "        Q32  F.  . 

O3^l8 

'         "    1832  F 

0-1718 

ft 

'         "    2192  F    

.03818 

it 

.O3IQ 

Regnault. 

'          liquid                                 . 

07^72 

'             32  —  212  F       

.077 

Dulong  &  Petit. 

•  O7^ 

Antimony                                     . 

OCQ77 

Regnault 

«         -52  —  =,72  F. 

.CK47 

Dulong  &  Petit. 

Bismuth    

.  03084 

Regnault. 

Gold 

07^44 

Silver      .        .        .  .      .  .        

O^7OI 

it 

"      32  —  ^72    F.  . 

.o6ll 

Dulong  &  Petit. 

Alanganese 

144  1  1 

Regnault 

Iridium     

1887 

Tungsten  

.o^6^6 

«< 

The  following  table  exhibits  the  relationship  between  the 
combining  numbers  and  specific  heats  of  the  metals;  the 
product  of  specific  heat  and  of  combining  number  is  seen 
to  be  very  nearly  constant,  as  shown  by  Kopp,  who  also  makes 
this  product,  or  the  *'  atomic  specific  heat,"  6.4  for  42  ele- 
ments, including  all  in  this  table.  Kopp  also  verifies  the 
law  of  Woestyn  and  Gamier,  finding  the  specific  heat  of  the 
molecule  equal  to  the  sum  of  the  specific  heats  of  the  con- 
stituent atoms. 


QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.         33 
TABLE  XL*. 

SPECIFIC   HEATS  AND    COMBINING  'NUMBERS. 


METALS. 

COMBINING 
NUMBERS. 

SPECIFIC  HEAT 
(REGNAULT). 

PRODUCT 

Aluminium     .        

27 

O.2I41* 

<  8 

Antimony  

122  • 

o  .  0508 

6  i 

Arsenic 

•je. 

o  0814 

6  i 

Bismuth      

2IO 

o  .  0308 

6  < 

Cadmium  

112 

0.0567 

6  •* 

Copper                                 

6^.«; 

o  oom 

6  o 

Gold  

196 

o  0^24 

6   4 

Lead  

207 

0.0^14 

6  4 

Iron             .        .... 

5° 

o  1138 

6  I 

Alagnesium  

24. 

O.24QQ 

6  o 

M  an  jjanese 

c  s 

O    1217 

6    7 

Mercury  (solid) 

2OO 

O    ^25 

u.  / 

6  e. 

Nickel      

en 

O.IoSg 

6   4 

106 

O.O^Q'? 

6  q 

Platinum 

IQ7.6 

O  O^2Q 

6   e. 

Potassium  ... 

-2Q.I 

O.  l6QC, 

6  «; 

108 

O   O^7O 

6   2 

Sodium            .... 

27 

O    2Q^4 

6    7 

Tin       

118 

w.^yj^ 
O.O5O2 

6  6 

Zinc  

65 

0.0956 

6.2 

The  specific  heats  are  slightly  variable  with  change  of  tem- 
perature. This  change  has  been  carefully  studied  only  in  a  few 
cases.  Holman  deduces,*  by  collating  results  of  experiments 
published  by  known  authorities,  for  the  specific  heat  of  iron  : 


k  =  0.10687  +  o.oooo304(/°  —  32)  +  o.ooooooo238(/—  32)*  > 
k  =  0.10687  +  Q.0000547/  +  o.ooooooo428/2  j" 

for  the  Fahrenheit  and  Centigrade  scales  respectively. 
For  platinum  he  obtains : 

k  =  0.0328  +  o.ooooo3022(/—  32)  +  0.000000000009  (/  —  32)', 
k  —  0.0328  +  0.00000544/  +  0.0000000000 1 6/2, 


(I) 


or,  very  nearly, 


k  =  0.03208  +  0.00000304  (t  —  32) ) 
k  —  0.03208  +  0.00000547/1      f 


*  Journal  Franklin  Institute,  August,  1882. 


34   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

The  figures  given  in  Table  XI.  are  mean  values  be- 
tween the  temperatures  of  freezing  and  of  boiling,  of  the 
quantity  of  heat,  in  thermal  units,  required  to  produce  a 
change  of  temperature  of  one  degree.  Their  values  have 
been  shown  by  Dulong  and  Petit  to  increase  with  the  rise  of 
temperature,  as  does  the  specific  heat  of  water  itself.  When 
melted  their  specific  heats  are  greater  than  when  solid. 

The  specific  heats  represent  the  number  of  units  of  water 
which  would  be  raised  in  temperature  one  degree  by  the 
addition  of  the  amount  of  heat  which  would  raise  one  unit  of 
weight  of  the  metal  one  degree.  Specific  heat  is  sometimes 
called  "  Capacity  for  heat." 

25.  The  Expansion  of  the  Metals  by  increase  of  tem- 
perature is  exhibited  by  the  following  table  of  coefficients  of 
linear  expansion. 

The  figures  represent  the  extension,  in  parts  of  its  own 
length,  of  a  bar  of  the  given  metal  during  a  rise  in  tempera- 
ture from  the  freezing  to  the  boiling  point  of  water. 

TABLE  XII. 

LINEAR   EXPANSIONS    OF    SOLIDS. 


EXPANSION    BETWEEN 
320F.(o°C.)AND2I20F.(lOO°C.) 

AUTHORITY. 

Glass 

o  000872  to  o  000918 

Lavoisier  and  Laplace. 

0.000776  to  0.000808 

Roy  and  Ramsden. 

Copper 

o  001712  to  o  001722 

Lavoisier  and  Laplace 

Brass  

o  001867  to  o  001890 

o  001855  to  0.001895 

Roy  and  Ramsden. 

Iron            .  . 

O   OOI22O  to  O   OOI235 

Lavoisier  and  Laplace 

Steel  (untempered)  .  .  . 
"    (tempered) 

0.001079  to  0.001080 
o  001240 

<(                      t  ( 

Cast  Iron  

O   OO  1  1  09 

Roy  and  Ramsden. 

Lead 

o  002849 

Tin    

o  001938  to  o  002173 

<«                      « 

«                      « 

Gold 

o  001466  to  o  001552 

«                      « 

o  000884 

Zinc 

o  002976 

Daniell 

QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.       35 

Chancy  gives*  the  following  values  of  the  coefficients  of 
linear  expansion,  at  ordinary  temperature,  as  recalculated  by 
him,  and  corrected  for  the  author,  from  selected  data,  for  the 
Standards  Office  of  the  British  Board  of  Trade. 

TABLE    XIL*. 

EXPANSIONS  OF   SOLIDS. 


FOR  i°  F. 

FOR  r  C. 

AUTHORITY. 

0.00001234 

O.OOOO222I 

Fizeau. 

cryst  

0.00000627 

0.00001129 

Brass  ca-t                   

0.00000957 

0.00001722 

Sheepshanks 

"      plate  

0.00001052 

0.00001894 

Ramsden. 

"     sheet 

0.00000306 

o.  00000^50 

Kater. 

Bronze,  Baileys, 
Cop.,  17  ;  tin,  25  ;  zinc,  i. 

0.00000986 
O.OOOOOQ7S; 

0.00001774 
0.00001775 

Clarke. 
Hilgard. 

Coooer 

0.00000887 

0.00001596 

Fizeau. 

Gold  

0.00000786 

O.COOOI4I5 

Chandler  &  Roberts. 

o  00000356 

O.COOOO64I 

Fizeau. 

Lead                         

0.00001571 

0.00002828 

Mercury  (cubic  expan.)  

0.00009984 
o  00004695 

o  00017971 
0.00001251 

Regnault  &  Miller. 
Fizeau. 

Osmium               .  .      ........ 

0.00000317 

0.00000570 

tt 

Palladium   

0.00000556 

O.OOOOIOOO 

Wollaston. 

Pewter 

o  00001129 

0.00002033 

Daniell. 

Platinum     

0.00000479 

0.00000863 

Fizeau. 

'*        CfO  ;  indium,  10.  .  .  . 
"        85;         "        15...- 
Silver             

0.00000476 
0.00000453 

0.00001079 

0.00000857 
0.00000815 
0.00001943 

it 

Chandler  &  Roberts. 

Tin     

0.00001163 

0.00002094 

Fizeau. 

0.00001407 

0.00002532 

Baeyer. 

"    8  tin  i     

0.00001496 

0.00002692 

Smeaton. 

These  coefficients  are  not  absolutely  constant,  but  vary 
with  the  physical  conditions  of  the  metals.  They  are  not  the 
same  with  the  same  material  in  its  forms  of  cast,  rolled,  ham- 
mered, hardened,  or  annealed  metal.  The  value  of  the  co- 
efficient of  expansion  also  increases  slightly  with  increase  of 
temperature. 

To  determine  the  length,  Lr,  of  a  bar  at  any  given  tem- 
perature, /',  knowing  its  length,  Z,,  at  any  other  temperature, 
/,  we  have  the  formulas  : 


*  Calculations  of  densities  and  expansions  ;  report  by  the  Board  of  Trade  ; 
printed  for  the  House  of  Commons,  London,  1883. 


36  MATERIALS  QF  ENGINEERING—  NON-FERROUS  METALS. 


, 


I   + 


at 
T8o 


,  for  Fahr.  scale, 


L(I  +  ^-} 

T,  \  lOOj        ,        „  , 

2J  =  «^_     for  Cent,  scale, 
at 

100 

where  a  is  the  coefficient  given  above. 

TABLE  XIII. 

EXPANSIONS    OF    VOLUME. 


•     •      (3) 


..      (4) 


• 

PER  DEGREE  CENT.* 

o°  C.  (32"  F.)  to 
ioor'  C.  (212°  F.). 

Glass  

.00002  to  .00003 

.002  to  .003 

Iron 

000035  to  000044 

0035  to  0044 

Copper.  . 

.000052  to  000057 

0052  to  .0057 

Platinum  

.000026  to  .000029 

.0026  to  .0029 

Lead 

000084  to  000080 

0084  to  0089 

Tin  

.000058  to  000069 

.0059  to  .0069 

Zinc  

.OOOO87  to  OOOOQO 

.0087  to  .0090 

Brass  .  . 

000053  to  000056 

0053  to  0056 

Steel  

.000032  to  000042 

.0032  to  .0042 

Cast  Iron  about 

ooocm 

.00^1 

These  results  are  partly  from  direct  observation,  and 
partly  calculated  from  observed  linear  expansion,  which  is 
one-third  the  cubical  expansion. 

26.  The  Fusibility  of  the  Metals,  or  their  property  of  be- 
coming liquid  at  a  temperature  which  is  always  the  same  for 
the  same  metal,  is  a  quality  which  has  an  important  bearing 
upon  their  useful  applications  in  the  arts. 

All  solids  which  do  not  undergo  decomposition  by  heat 
before  reaching  that  temperature  have  definite  "melting 
points." 

The  metals  differ  more  widely  in  their  temperatures  of 


Abridged  from  Watts's  "Dictionary  of  Chemistry. 


QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.        37 


fusion  than  even  in  density.  Solidified  mercury  melts  at 
nearly  40°  below  zero,  Fahr.  (—  40°  Cent.) ;  while  platinum 
requires  the  highest  temperature  attainable  with  the  oxy- 
hydrogen  blow-pipe.  The  more  common  metals  fuse  at  tem- 
peratures quite  readily  attainable,  although  none  of  them 
melt  at  temperatures  approaching  those  ordinarily  met  with 
in  nature. 

Some  of  the  metals  may  even  be  readily  volatilized,  and 
probably  all  are  vaporized,  to  a  slight  degree  at  least,  at  very 
high  temperatures.  Mercury  boils  at  330°  Cent.  (626°  Fahr.). 
Zinc  can  be  distilled  at  a  bright  red  heat,  and  copper  and 
gold  are  known  to  give  off  minute  quantities  of  vapor  at 
temperatures  frequently  occurring  during  the  process  of  man- 
ufacture. 

The  low  temperatures  of  fusion  of  tin,  lead,  bismuth,  and 
antimony,  allow  of  their  being  readily  applied  as  solders, 
either  alloyed  or  separately.  Cast  iron,  copper  and  its  alloys, 
and  other  metals,  melt  at  temperatures  which  are  easily 
reached,  and  the  iron  and  the  brass  founders  are  thus  enabled 
by  the  process  of  moulding  and  casting,  to  produce  the  most 
intricate  forms  readily  and  cheaply,  and  thus,  when  desired, 
to  obtain  large  numbers  of  precise  copies  of  the  same  pattern. 

The  melting  points  of  some  of  the  more  important  metals 
are  as  follows : 

TABLE  XIV. 

TEMPERATURE  OF    FUSION  OF  COMMERCIAL  METALS. 


FAHR. 

CENT. 

Mercury      .    ....     

—  39° 

—  39° 

Tin  

420 

216 

Bismuth                     .                .... 

400 

254 

Lead  

7 
630 

332 

Zinc  

700 

371 

Silver                                          

1,280 

693 

1,870 

1,021 

2,550 

1,118 

2,750 

1,510 

4,000  (?) 

2,201  (?) 

38   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

The  temperatures  of  fusion  of  pure  iron,  or  of  wrought 
iron,  are  very  high,  and  are  not  precisely  known,  no  means 
of  accurate  measurement  having  yet  been  applied  to  their 
determination. 

The  following  very  complete  table  will  serve  for  reference 
in  more  extended  work.* 


TABLE  XV. 


MELTING   POINTS   OF   PURE   METALS. 


FUSIBLE  ABOVE   RED   HEAT. 

FUSIBLE   BELOW   RED    HEAT. 

F. 

C. 

F. 

C. 

Silver               .  .    .  . 

+  1873°     +  1023° 
1996          1091 

2Ol6             IIO2 
2786             1530 

?  Highest  heat  of 
the  forge. 

Do  not  melt  in  the 
forge. 

Fusible  only  in 
Oxyhydrogen 
flame. 

Mercury    .  .        .... 

-39° 
+  101.3 

144-5 
207.7 
356 
442 
442.5 
497 
56i 
617 
6i5  (?) 

773 
red 

-39°  -8 
+  38.5 
62.5 
97.6 
1  80 
227.8 
228 

259 
294 

325 
324 

412 
heat. 

Copper  .  . 

Rubidium  

Gold 

Potassium 

Cast  Iron  

Sodium  

Pure  Iron,                "1 
Nickel, 
Cobalt,                      \ 
Manganese, 
Palladium, 
Molybdenum,          1 
Uranium, 
Tungsten, 
Chromium, 
Titanium, 
Cerium, 
Osmium, 
Iridium, 
Rhodium, 
Platinum, 
Tantalum, 

Lithium 

Tin     

Cadmium  

Bismuth  

j  Thallium 

Lead     

Arsenic     .... 

Zinc  

Antimony 

Latent  Heat. — In  passing  from  the  solid  to  the  liquid 
state,  a  certain  amount  of  heat  disappears,  being  expended 
in  producing  this  change  of  physical  conditions. 

Latent  Heat,  as  this  is  called,  varies  in  amount  with  dif- 


For  approximate  values  of  temperatures  of  fusion  of  alloys,  see  later. 


QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.        39 

ferent  substances.     In  Table   XVI.  are  the  latent  heats  of 
several,  as  obtained  by  M.  Person,  expressed  in  thermal  units.* 


TABLE  XVI. 

LATENT   HEATS   OF   METALS. 


CENT. 

FAHR. 

Tin           

14.25 

2<$.  6«? 

Bismuth  

12.64 

22.75 

Lead                       .                          ... 

c    -17 

9.67 

Water  

7Q.25 

142.65 

Silver 

21    O7 

V]  .&\ 

Cadmium       ... 

i-?.  66 

24-  5Q 

27.  Chemical  Character. — Chemically,  the  metals  exhibit 
the  same  variation  of  properties  as  physically,  and  the  line  of 
demarcation  between  the  metals   and  the   metalloids  is   no 
more  definitely  fixed.    They  are  acid  or  basic  in  combination, 
and  resemble  the  metalloids  more  or  less  nearly  in  chemical 
action,  according  to  the  proportion  as  well  as  the  nature  of 
the  elements  with  which  they  combine.     Their  oxides  are 
usually  basic,  but  often  acid.     The  alkaline  metals  unite  with 
oxygen  with  great  rapidity  to  form  alkaline  oxides  ;  the  com- 
mon "  useful  "  metals   are   oxidized  readily,  but   less   freely 
than  the  preceding,  and  gold,  silver,  platinum,  and  others, 
have   little   affinity  for  oxygen,  and  do   not  easily  corrode. 
Nearly  all   metals   combine   freely  with   sulphur,   and   their 
sulphides  form,  in  some  cases,  extensive  deposits  which  are 
worked  for  the  market. 

28.  Alloys  are  formed   by  fusing  together  two  or  more 
metals.     In  the  alloys,  metallic  qualities  and  chemical  prop- 
erties are  not  always   completely   altered  or  masked,   as  is 
the  case  in  chemical  combinations  with  the  non-metals. 

*  This  thermal  unit  is  the  quantity  of  heat  required  to  raise  the  temperature 
of  unity  in  weight  of  water  at  maximum  density,  one  degree  in  temperature. 
For  values  of  constants,  relating  to  the  non-ferrous  metals,  expressed  in  "  C.  G. 
S."  units,  see  Appendix,  Part  I. 


40  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

The  physical  properties  of  the  alloys  are,  however,  some- 
times quite  different  from  those  of  the  constituent  metals, 
notwithstanding  the  fact  that  the  compounds  formed  are 
apparently  not  definite,  as  in  cases  of  purely  chemical  combi- 
nations. It  would  appear  probable  that  the  force  of  chemi- 
cal affinity  performs  some  part  in  the  formation  of  the  alloy. 
It  is  not  improbable  that  a  definite  compound  is  usually 
formed  which  either  dissolves,  or  is  dissolved  in,  any  excess 
of  either  constituent  which  may  be  present. 

Examples  of  alloys  are  seen,  in  gold  and  silver  coins,  in 
which  the  precious  metals  are  hardened  by  alloying  them 
with  copper,  to  give  them  greater  durability.  Copper  is  too 
soft  and  tough  to  allow  of  its  being  conveniently  worked,  and 
it  is,  therefore,  for  most  purposes,  alloyed  with  tin  or  zinc,  and 
these  alloys — bronze  and  brass — are,  by  varying  the  propor- 
tions of  the  metals  used,  adapted  to  a  wide  range  of  useful 
application.  Alloys  of  copper  and  tin  exhibit  strikingly  the 
fact,  noted  above,  that  the  alloy  may  have  widely  different 
properties  from  either  constituent. 

Speculum  metal  is  composed  of  33  per  cent,  of  tin  fused 
with  67  per  cent,  of  copper.  Its  color  is  nearly  white,  it  is 
extremely  hard,  exceedingly  brittle,  and  takes  a  magnificent 
polish.  The  latter  property  gives  it  value  for  reflectors  of 
telescopes.  Its  metallic  lustre  resembles  neither  of  its  con- 
stituents, and  its  tenacity  is  but  about  20  per  cent,  of  that  of 
the  weaker  metal. 

Type  metal,  also,  formed  by  alloying  lead  and  antimony, 
in  the  proportions  of  four  of  the  former  and  one  of  the  latter, 
is  a  hard  alloy,  capable  of  being  cast  in  moulds,  taking  form 
very  perfectly,  and  it  differs  greatly  in  its  properties  from 
either  lead  or  antimony. 

It  is  usually  found  that  the  temperature  of  fusion  of  an 
alloy  is  below,  and  often  considerably  below,  that  of  either 
constituent  metal.  The  strength  of  alloys  is  often  greater 
than  that  of  the  metals  composing  them. 

The   characteristics  of   the    alloys   will   be    discussed    at 
greater  length  when  treating  of  those  compounds  hereafter. 
The  minimum  percentage  of  metal  in  paying  ores  varies 


QUALITIES  OF  THE  METALS  AND  THEIR  ALLOYS.       41 

with  the  value  of  the  metal  in  the  market,  and  the  cost  of 
reduction  and  transportation ;  the  following  may  be  taken  as 
fair  averages : 

Iron 25  to  40  per  cent. 

Lead 20  to  25 

Zinc 201025         " 

Antimony 201025         " 

Copper 2  to    2.5     " 

Tin i  to    1.5     *' 

Mercury I  to    2.5 

Silver 0.0005      to  o.ooio  per  cent 

Platinum o.oooi      to  0.0002         " 

Gold o.oooooi  to  o.ooooi       " 

Where  two  metals  exist  together,  as  copper  and  silver, 
lead  and  silver,  iron  and  manganese,  the  ore  may  be  reduced 
for  the  one,  and  the  other  obtained  incidentally,  at  less 
expense,  when  in  even  smaller  quantities  than  above  given. 


CHAPTER    II. 

COPPER,   TIN,   ZINC,    LEAD,   ANTIMONY,   BISMUTH,   NICKEL, 
ALUMINIUM,  ETC. 

29.  Copper  (Latin  Cuprum,  Cu.)  has  been  known  to  man- 
kind from  some  very  early,  and  even  prehistoric,  period,  and 
was  applied  in  the  manufacture  of  tools  and  useful  implements, 
probably  long  before  iron  was  used,  or  even  known.  It  exists 
native  and  is  comparatively  easily  reduced  from  its  ores  and 
worked,  and  hence  could  be  obtained  and  worked  at  a 
time  when  the  art  of  reducing  the  comparatively  refractory 
ores  of  iron  had  not  been  acquired. 

Tubal  Cain  worked  "  in  brass  and  in  iron  " ;  the  ancient 
Egyptians  mined  copper  in  the  neighborhood  of  Sinai,  and  of 
it  made  an  alloy  which  was  used  in  making  their  mining  and 
quarrying  tools  and  are  supposed  by  Wilkinson  and  other 
Egyptologists,  to  have  been  able  to  temper  it  as  we  temper 
steel.  It  is  more  likely,  however,  that  they  knew  only  how 
to  produce  and  harden  the  alloys  of  copper  and  tin. 

All  the  more  civilized  nations  succeeding  those  contempo- 
rary with  Cheops  used  bronze  extensively  in  making  statuary 
and  monuments,  and  the  Greeks  and  Romans  made  a  statuary 
bronze,  taking  a  " patina"  unexcelled  in  later  times.  Their 
foundry-work  was  fully  equal  to  that  of  the  moderns.  It  was 
also  used  in  coinage  by  these  nations  as  it  is  used  to-day. 

The  prehistoric  nations  of  America  used  large  quantities 
of  copper,  quarrying  it  in  all  those  districts  in  the  neighbor- 
hood of  Lake  Superior  which  have  been  recently  worked  for 
mass  copper,  and  their  tools  are  still  occasionally  found  in 
the  old  workings.  It  was  worked  in  Mexico  by  the  Aztecs, 
and  by  the  same  race  in  Chili  and  Peru,  before  the  discovery 


COPPER.  43 

of  those  countries  by  the  Spaniards.  The  bronze  used  by  the 
Aztecs  was  of  similar  composition  to  that  made  by  their 
Asiatic  contemporaries,  and  that  used  frequently  in  modern 
times  when  a  tough,  as  well  as  strong,  bronze  is  desired — 94 
per  cent,  copper,  6  per  cent.  tin.  Bronze  implements  of 
great  age  have  been  found  in  all  parts  of  Europe,  and  so  ex- 
tensively was  it  used  in  the  period  preceding  that  in  which 
iron  became  common  that  that  period  has  been  denominated 
the  "  Bronze  Age." 

According  to  Lubbock,*  copper  was  mined  in  many  locali- 
ties, and  the  knowledge  of  mining,  alloying  it  and  of  casting  in 
bronze  was  brought  into  Europe  from  the  East.  The  tin 
with  which  it  was  alloyed  was  obtained,  in  the  time  of  the 
Phoenicians,  from  Cornwall.  The  forms  of  the  bronze  im- 
plements found  in  Europe  and  in  America  are  often  strikingly 
similar.  Bancroft  f  states  that  the  American  Indians  were 
reported  by  Cabot,  in  1598,  to  be  familiar  with  this  metal  and 
its  use. 

30.  Qualities. — The  metal  has  a  deep  red  color,  the  only 
metal  except  titanium  having  that  color,  is  heavy  (S.  G.  8.8  to 
8.93)  very  malleable  and  ductile  and  has  considerable  tenacity. 
Its  hardness  is  usually  rated  at  2.5  or  3.  When  warm,  and 
when  rubbed  with  the  hand,  it  gives  out  a  strong  odor  of  a 
peculiar  and  somewhat  disagreeable  character.  Commercial 
copper  is  contaminated  with  silver,  lead,  antimony  and  iron ; 
although  the  native  copper,  as  much  of  that  obtained  from 
Lake  Superior,  is  sometimes  almost  chemically  pure. 

The  melting  point  of  copper  is  given  by  Pouillet  as  2050° 
Fahr.  (1121°  C.)  and  vaporization  occurs  at  the  white  heat, 
the  vapors  burning  with  the  green  flame  which  gives  the 
characteristic  lines  of  this  metal  in  the  spectroscope.  It 
is  a  remarkably  good  conductor  both  of  heat  and  electricity. 
Copper  does  not  oxidize  in  dry  air  at  ordinary  temperatures, 
but  does  so  rapidly  in  a  moist  or  acid  atmosphere,  and  at 
temperatures  approaching  the  red  heat. 

Of  this  metal  from   125,0x30  to  150,000  tons  are  annually 

*  "  Prehistoric  Times."  f Vo1-  »•  P-  I2  (Ed-  l856-) 


44    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

consumed,  principally  from  the  United  States,  Cornwall, 
Chili  and  Bolivia.  It  is  supplied  in  the  form  of  bars,  wire, 
sheet  and  ingots,  which  latter  are  re-melted  to  obtain  copper 
and  alloys  in  castings.  It  is,  next  to  iron,  the  most  important 
and  useful  of  the  metals.  Its  valuable  properties  will  be  de- 
scribed at  greater  length,  presently. 

31.  Copper  Ores  are  distributed  very  widely  over  the 
earth's  surface  and  are  found  in  every  large  political  division 
of  the  world.  It  exists  in  a  great  variety  of  forms,  usually  as 
sulphide  or  oxide;  but  in  some  cases, as  in  the  United  States, 
on  the  south  shore  of  Lake  Superior,  is  found  in  the  form  of 
native  copper  and  in  enormous  quantities.  Very  large  quan- 
tities are  now  mined  in  Montana,  Arizona,  and  other  western 
districts. 

Metallic  copper  occurs  in  masses,  in  flakes  and  sheets,  in 
threads,  and  in  spongy  masses  dissemimated  through  rock 
crevices,  earthy  gangue  or  even  solid  rock  masses.  Enor- 
mous blocks  and  extensive  masses  are  found  and  worked  in 
several  of  the  mines  of  Lake  Superior.  These  great  blocks 
sometimes  weigh  several  hundred  tons.  In  this  condition  it 
is  one  of  the  most  expensive  ores  of  copper ;  for  the  metal  is 
excessively  tough,  and  cannot  be  blasted,  but  must  be  pre- 
pared for  the  market  by  being  cut  up  with  tools  ;  and  the 
presence  of  siliceous  gangue  in  the  mass  renders  this  opera- 
tion very  difficult.  In  the  deposits  worked  in  and  near  the 
Calumet  and  Hecla  mine  of  that  district,  it  exists  in  the  red 
conglomerate  in  a  peculiar  form,  permeating  the  rock  very 
uniformly  in  just  such  a  proportion  as  gives  maximum  ease 
and  cheapness  of  mining  and  preparation. 

The  metallurgists  find  that  comparatively  few  of  the  cop- 
per minerals  are  of  much  importance,  by  far  the  largest  pro- 
portion of  this  metal  annually  produced  by  the  mines  of  the 
world  being  obtained  from  copper  pyrites. 

Phillips  gives  the  following  list  of  the  commercial  ores  of 
copper.* 

Native  Copper  is  cubical,  occurs  crystallized  in  octahedrons, 
sometimes  modified,  lamellar,  filiform,  or  arborescent,  and  has 
a  specific  gravity  —  8.83.     No  known   locality  produces  such 
*  Vide  "  Elements  of  Metallurgy  ;"  J.  A.  Phillips.     Lond.,  1874. 


COPPER 

large  quantities  as  the  region  of  Lake  Superior,  where  it  occurs 
in  veins  intersecting  trap  rocks,  frequently  associated  with 
metallic  silver.  In  small  quantities,  native  copper  is  of  fre- 
quent occurrence,  but  except  in  the  region  above  mentioned, 
it  is  not  of  much  importance  as  an  ore.  It  is  generally  re- 
markable for  great  toughness. 

Cuprite  (red  oxide  of  copper) — composition,  Cu2O — is  cub- 
ical, generally  in  cubes  and  octahedrons,  of  a  ruby-red  color, 
with  a  specific  gravity  —  6,  and  contains,  when  pure,  88.80 
per  cent,  of  copper. 

Melaconite  (black  oxide  of  copper) — composition,  CuO — is 
cubical  ;  rarely  found  crystallized,  but  more  commonly 
earthy ;  is  massive,  or  pulverulent,  affording,  when  pure, 
79.82  per  cent,  of  copper. 

Malachite  (green  carbonate  of  copper)  crystallizes  in  the 
oblique  system,  the  crystals  being  often  very  complicated  ; 
occurs  more  frequently  massive  or  incrusting  the  surface, 
being  botryoidal  or  stalactitic.  The  specific  gravity  =  3.7  to 
4.1.  Its  composition  is  CuCO3,  CuH2O2,  yielding,  when  pure, 
57.33  per  cent,  of  copper.  This  mineral  frequently  occurs 
near  the  surface,  in  veins  producing  sulphides  and  other  ores 
of  copper,  and  has  probably  been  derived  therefrom  by  at- 
mospheric agencies. 

A2urttr(b\ue  carbonate  of  copper) — composition,  2CuCO3, 
CuH2O2 — crystallizes  according  to  the  oblique  system,  and 
also  occurs  massive.  Its  specific  gravity  is  3.5  to  8.81  ;  con- 
taining, when  pure,  55.16  per  cent,  of  metallic  copper.  It 
occurs  largely  in  South  Australia,  and  formerly  at  Chessy, 
near  Lyons ;  and  is  hence  sometimes  called  Chessylite. 

Chalcopyrite  (copper  pyrites) — composition,  Cu2S,  Fe2S3 — is 
prismatic,  often  in  hemihedral  forms,  though  more  commonly 
massive,  with  specific  gravity  =  4.2  ;  containing,  when  pure, 
34.81  per  cent,  of  copper.  This,  which  is  the  most  important 
ore,  rarely  contains,  as  sent  to  market,  more  than  12  per  cent. 
of  that  metal,  and  frequently  less. 

Bornite  (purple  copper  ore)  crystallizes  in  the  cubical  system, 
and  has  a  specific  gravity  4.4  to  5.5.  Its  composition  varies, 
sometimes  3Cu2S,  Fe2S3 ;  copper  from  50  to  70  per  cent. 


46  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Chalcocite  (gray  sulphide  of  copper)  is  prismatic,  and  of 
specific  gravity  5.7 ;  its  composition  is  Cu2S,  yielding,  when 
pure,  79.70  per  cent,  of  copper. 

The  copper  sent  into  the  market  from  the  Lake  Superior 
district  is  principally  derived  from  crushed  low-grade  rock, 
containing  native  copper ;  that  coming  from  the  southern 
Rocky  Mountains  is  derived  from  oxides,  and  that  from  the 
Butte  district  of  Montana  and  from  Arizona  is  obtained  from 
argentiferous  ores.  The  copper  smelted  in  the  Appalachian 
sections  is  from  pyritous  ores.  Altogether  they  yield  between 
80,000  and  90,000  tons  annually.  The  output  in  1845  was 
but  loo  tons,*  that  in  1891  was  about  280  millions  of  pounds 
(nearly  175,000,000  kilogs.),  valued  at  12  cents  per  pound,  or 
over  $30,000,000,  and  was  increasing  at  the  rate  of  10  to  15 
per  cent,  annually.  Much  of  this  product  is  exported.  The 
refining  is  done  in  works  situated  at  Baltimore,  Md.,  Orford, 
N.  Y.,  and  in  various  other  scattered  localities  in  the  United 
States,  as  well  as  by  the  mining  companies. 

The  production  of  Great  Britain  is  very  small,  and  that  of 
Spain  and  Chili  is  enormously  great. 

Copper  smelting  in  the  United  States  is  conducted,  by 
three  principal  methods,  according  to  the  character  of  the 
ores.  These  are  :  f 

Fusion  of  native  copper  and  refining; 

Fusion  of  carbonates  and  refining  ; 

Reduction  of  sulphuretted  ores  and  refining. 

Lake  Superior  copper  is  of  the  first  class.  It  is  melted 
down  as  received  with  its  gangue  and  with  6  or  8  per  cent, 
limestone  and  10  per  cent,  refinery  slags.  The  charges  are 
about  12  tons  each,  which  are  worked  in  a  large  reverberatory 
furnace  about  12  hours.  The  slags  are  skimmed  and  the 
richer  grades  are  refined,  while  the  remainder  form  a  part  of 
the  next  charge.  The  refining  and  ladling  take  5  hours. 

Cupola  furnaces  are  sometimes  used,  which  take  20  tons  at 
a  run,  of  which  40  or  45  per  cent,  is  limestone,  30  to  35  per 

*  "  Metallic  Wealth  of  the  U.  S."  :  Whitney. 

|  J.  Douglas,  Jr.,  in  "  Mineral  Resources  of  the  U.  S."      Gov't  Print.  (GeoL 
Survey  ;  Interior  Dept.),  Washington,  D.C.,  1883. 


REDUCTION  OF  COPPER  ORES.  47 

cent,  anthracite  coal  and  4  per  cent,  copper.  The  lining  fur- 
nishes a  considerable  amount  of  silica  and  is  rapidly  cut  out. 
The  Bessemer  process  is  also  used  in  reducing  copper. 

32,  The  Processes  of  Reduction  of  copper  ores  differ  with 
their  composition.     The  oxides  and  carbonates  are  easily  re- 
duced, by  fusion,  in  presence  of  carbon,  with  a  siliceous  flux. 
The  copper  is  promptly  reduced  to  the  metallic  state.     Some 
loss  is  usually  met  with  in   consequence   of   the  tendency  of 
the  oxide  to  form  a  silicate,  and  this  is  checked  by  supplying 
either  an  alkaline  base,  usually  lime,  or  by  mixing  with   sul- 
phuretted ores,  of  which  the  sulphur  unites  with  the  oxygen 
present  and  thus  permits  complete  reduction. 

The  sulphides  are  usually  first  roasted  and  thus  converted 
to  a  considerable  extent  into  oxide.  This  roasted  ore  is  then 
smelted,  sometimes  in  reverberatory  and  sometimes  in  blast 
furnaces,  and  this  roasting  and  smelting  is  repeated  until 
a  "  regulus  "  is  obtained  consisting  of  a  nearly  pure  sulphide. 
This  product  is  finally  roasted  with  free  access  of  air  until, 
having  been  brought  to  a  certain  state,  in  which  sulphide  and 
oxide  exist  in  the  right  proportion,  a  double  decomposition 
occurs,  yielding  sulphurous  acid  and  metallic  copper  (2CuS-f 
Cu2O  =  SO2  +  Cuc)  which  latter  is  of  fair  degree  of  purity,  and 
is  known  either  as  "  coarse  copper,"  or  "  blister  copper,"  etc., 
etc.  This  is  finally  purified  before  it  is  sent  into  the  market 
as  ingot  copper.  The  final  process  consists  in  melting  down 
in  the  presence  of  an  oxidizing  flame  and  with  fluxes,  and, 
after  removal  of  slag,  "  poling  "  or  stirring  with  green  birch 
rods  or  poles  to  produce  thorough  mixture  and  to  decompose 
all  oxide.  Care  and  skill  are  required  to  prevent  either 
"  underpoling,"  which  would  leave  oxide  in  the  metal,  or 
"  overpoling,"  which  reduces  other  metals  and  makes  an  alloy 
of  reduced  value. 

This  last  process  of  refining  is  the  only  one  necessary  in 
the  treatment  of  the  native  copper  of  Lake  Superior. 

33.  Details  of  Reduction  of  Copper  Ores. — In  detail, 
these  processes  arc  very  complex,  although  sufficiently  simple 
in  their  theory.     The  process  of  reduction  usually  practised 
consists  of  roasting  to  expel  sulphur  and  arsenic,  melting  to 


48   MATERIALS  OF  ENGINEERING-NON-FERROUS  METALS. 

flux  out  iron  oxide  by  siliceous  fluxes,  and  roasting  and  smelt- 
ing in  one  operation  to  obtain  the  commercial  metal. 

The  first  operation  is  that  of  breaking  up  the  ore  into  small 
and,  as  nearly  as  may  be,  uniform  pieces,  removing  useless 
gangue  and  assorting  the  ore  in  such  a  manner  as  to  facilitate 
the  processes  of  reduction.  The  next  process  is  that  of  cal- 
cining, roasting,  about  three  tons  at  a  time,  in  a  reverberatory 
furnace  on  a  long  and  wide  level  hearth — often  15  or  16  feet  by 
12  or  14(4.6  or  4.9  metres  by  3.7  or  4.3) — where  it  is  spread  in 
a  thin  layer  and  exposed  to  the  action  of  the  flame.  The 
hearth  is  bricked  over  and  cemented  with  fire-clay  and  the 
roof  is  a  low  arch.  Openings  from  the  fire-place  admit  the 
heating  gases  ;  others  from  the  atmosphere  provide  for  oxida- 
tion by  the  admission  of  air ;  and  others  at  each  side  are 
arranged  for  the  discharge  of  the  roasted  ore  into  a  low 
arched  space,  or  chamber,  under  the  furnace.  The  ore  is 
admitted  through  openings  in  the  top  surmounted  by  hop- 
pers, into  which  it  is  filled  and  left  to  heat  gradually  until 
dropped  into  the  furnace. 

The  fuel,  a  soft  coal  or  a  mixture  of  bituminous  and  semi- 
bituminous  coal,  is  burned  with  restricted  air-supply,  and  the 
resulting  carbonic  oxide  passes  into  the  furnace,  where,  meet- 
ing the  required  air,  it  burns  to  carbon  dioxide,  and  the  long 
flame  sweeping  over  the  hearth,  heats  the  ore  to  the  tempera- 
ture needed  to  roast  it.  While  thus  exposed  to  the  heat  of 
the  burning  gas,  the  ore  is  continually  stirred  and  raked  over 
to  bring  all  parts  of  the  charge  into  contact  with  the  flame. 

During  this  process,  any  sulphur  present  is  exposed  to 
oxygen  at  high  temperature,  and  a  part,  but  never  all,  is 
oxidized,  passing  off  as  sulphurous  acid  ;  or  oxidizing  in  small 
amount  still  further,  it  unites  with  the  copper  to  form  a  sul- 
phate. The  arsenic  passes  off  as  white  arsenic,  arsenious 
acid,  in  the  form  of  vapor.  The  copper  also  combines,  to  a 
slight  extent,  with  oxygen,  to  form  the  suboxide  of  copper, 
and  any  salt  of  iron  present  in  sulphides  becomes  changed 
to  oxide. 

In  some  cases,  the  roasting  is  accomplished  by  indirect 
heating  and  out  of  contact  with  the  flame  from  the  grate, 


REDUCTION  OF  COPPER  ORES.  49 

and  the  vapors  thus  isolated  are  diverted  for  the  purpose  of 
converting  the  sulphurous  acid  into  sulphuric  acid,  which 
latter  is  collected  in  the  usual  way  in  leaden  chambers. 
Where  the  gases  from  the  fuel  mingle  with  the  vapors  of 
sulphur,  and  other  products  of  roasting,  they  are  often  all 
carried  into  a  "  condenser,"  in  which  a  spray  of  water  is 
introduced  to  wash  the  air  clean  before  discharging  it  into 
the  atmosphere. 

The  ore  is  now  ready  to  be  smelted.  If  any  ores  are  to 
be  treated  which  are  free  from  arsenic  and  sulphur,  they  are 
not  roasted,  but  are  mixed  with  the  other  ores  after  the  latter 
are  calcined,  and  the  mixture  is  then  smelted. 

The  smelting  furnace,  called  often  the  "  ore  furnace,"  is  a 
small  reverberatory  furnace,  fitted  with  a  comparatively  large 
grate,  and  having  a  hearth  so  formed  that  the  molten  ore 
may  lie  on  it  in  a  shallow  pool,  deepest  near  the  middle  of 
one  side  of  the  furnace.  The  charge  is  about  one  and  a  half 
tons  of  ore,  flux  and  slag  derived  from  a  later  operation,  of 
which  the  ore  amounts  to  about  two-thirds,  while  the  flux 
and  slags  make  up  the  other  third.  This  being  charged  upon 
the  bed  of  the  furnace,  the  slag  soon  melts,  and  the  whole 
charge  later  becomes  molten  and  "  boils  "  rapidly  with  disen- 
gagement of  sulphurous  acid.  In  the  course  of  four  hours, 
or  less,  the  attendant  uses  his  rubble,  stirring  the  charge 
thoroughly,  and  at  the  same  time  raising  the  heat  of  the 
furnace  until  the  coarse  metal  and  slag  separate.  When  this 
is  done,  the  "  matt "  or  "  regulus "  of  partly  refined  or 
"  coarse  metal "  is  tapped  off  into  a  cast-iron  box  having  a 
perforated  bottom,  through  which  it  runs  into  a  tank  contain- 
ing water,  and  thus  becomes  granulated.  The  slag  is  run 
into  moulds,  and  the  blocks  so  formed — of  silicate  of  iron, 
principally — are  useful  in  building. 

The  regulus  is  only  one-third  copper,  the  rest  being  sul- 
phur and  iron,  and  the  whole  being  a  sulphide  of  copper  and 
iron.  It  is  charged  again  into  the  roasting  furnace,  and 
calcined  for  twenty-four  hours,  the  workmen  raking  it  over 
en  or  twelve  times  in  the  interval,  as  the  sulphur  burns  out 
of  the  more  exposed  portions.  The  loss  of  about  one-half  the 


50  MATERTAZS  OF  ENGINEERING— NON-FERROUS  METALS. 

sulphur  reduces  the  charge  to  a  mixture  of  iron  oxide,  copper 
sulphide,  and  some  iron  sulphide. 

This  calcined  regulus  is  then  charged  with  slags  from 
later  processes  in  equal  or  greater  quantity,  and  with  any 
pure  oxides  or  carbonates  at  hand,  into  a  melting  furnace, 
and  there  held  in  fusion  about  six  hours,  when  the  resulting 
regulus  and  slag  are  tapped  off.  The  former  may  be  run 
into  water  as  before,  and  thus  made  "  fine  metal,"  or  cast  in 
pigs  as  "  blue  metal,1'  containing  about  seventy-five  per  cent, 
of  copper.  The  best  copper  is  found  in  the  pigs  last  cast, 
the  first  producing  a  less  pure  metal  called,  later,  "  bottoms." 
or  "tile  copper."  When  less  rich  in  copper,  it  is  again  cal- 
cined and  melted  to  obtain  block  or  coarse  copper,  contain- 
ing more  metal.  The  slag,  or  "  metal  slag,"  as  it  is  called, 
contains,  usually,  enough  of  copper  to  make  it  advisable 
to  re-work  it  with  the  ores,  as  already  described,  or  sepa- 
rately. 

Still  another  repetition  of  the  calcining  and  melting  proc- 
esses removes  a  part  of  the  remaining  sulphur,  and  yields 
what  is  called  "blistered  copper;"  the  "blisters"  on  the 
surface  of  the  ingots  giving  evidence  of  the  escape  of  sul- 
phurous acid  while  solidifying. 

Finally,  this  blistered  copper  is  re-heated  in  charges  of  six 
or  eight  tons  weight,  with  free  access  of  air,  and  the  arsenic  and 
sulphur  remaining  are  converted  into  arsenious  and  sulphur- 
ous acid,  and  the  iron,  lead,  tin,  and  other  oxidizable  impuri- 
ties are  converted  into  oxides  before  the  charge  is  allowed 
to  melt,  this  preliminary  operation  occupying  about  six 
hours.  The  metal  is  then  melted  down  and  sampled  to 
determine  how  the  process  of  "  toughening "  shall  be  con- 
ducted. This  consists  in  "  poling,"  or  stirring  the  molten 
charge  with  poles,  from  young  saplings  of  birch,  usually, 
until  sample  ingots  exhibit  the  density,  toughness,  fineness 
of  grain,  and  pure  copper  color  which  indicate  the  desired 
quality.  When  right,  or  at  "  tough-pitch,"  it  is  run  into 
ingot  moulds  and  becomes  "  tough-cake."  The  process  of 
poling  results  in  the  removal  of  the  oxygen  taken  up  by  the 
copper  in  the  earlier  processes  by  contact  with  the  hydro- 


REDUCTION  OF  COPPER  ORES.  5 1 

carbons  and  the  pure  carbon  of  the  wood.  Overpoling  causes 
the  absorption  of  carbon,  and  gives  the  same  brittlencss 
which  had  been  caused  by  oxygen  ;  and  the  avidity  with 
which  copper  takes  up  both  these  elements  makes  this  opera- 
tion one  demanding  great  care  and  skill. 

Where  sheet  copper  is  to  be  made,  lead  is  often  added 
before  casting,  to  give  greater  malleability,  by  fluxing  out 
the  tin  and  other  alloy ;  this  lead  is  oxidized,  and  is  all 
removed  again  with  other  oxides  in  the  slag. 

Modifications  of  this  process  are  adopted  with  leaner 
ores ;  and  the  melting  and  poling  only  is  necessary  with  pure 
native  copper,  such  as  is  mined  in  the  Lake  Superior  region 
in  the  United  States. 

Copper  is  reduced  at  Ore  Knob,  N.  C,  from  very  pure 
but  lean  ores,  containing  from  two  to  five  per  cent,  copper. 
These  ores  are  picked  over  carefully,  and  sent  to  the  calcin- 
ing ground,  where  they  are  roasted  in  heaps,  under  sheds  240 
to  300  feet  long  and  34  feet  wide,  the  piles  measuring  100 
tons  of  fresh,  or  50  tons  of  roasted  ore.  The  roasted  ore 
contains  four  to  five  per  cent,  copper. 

Fusion  of  the  ores  takes  place  in  furnaces  resembling 
cupolas,  and  the  mattes  are  smelted  in  the  same  kind  of  fur- 
nace. The  latter  contain  twenty  or  twenty-five  per  cent, 
copper.  These  "  single  mattes  "  are  roasted  in  heaps,  and 
fused  in  shaft-furnaces  for  black,  or  pig  copper,  and  "  double," 
or  concentrated  mattes.  This  black  copper  contains  ninety 
to  ninety-five  per  cent  metallic  copper,  some  iron,  and  other 
elements. 

The  mattes  are  re-worked,  and  the  crude  copper  is  refined 
in  reverberatory  furnaces,  taking  five  tons  at  a  charge  ;  the 
product  consists  of  99.8  per  cent,  metallic  copper. 

The  wet  processes  of  copper  extraction  are  divided  by 
Hunt  *  into  three  classes  : 

I.  Those  in  which  the  copper  in  sulphuretted  ores  is  ren- 
dered soluble  in  water,  after  roasting  them,  converting  them 
into  chlorides  or  sulphates. 

II.  Those  in  which  free  hydrochloric  or  sulphuric  acid  is 

*  Trans.  Am.  Inst.  Min.  Engineers,  vol.  x.,  p.  II. 


52   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

used  to  dissolve  the  metal  from  oxides  or  roasted  ores.  These 
are  usually  costly  processes,  and  are  seldom  practised. 

III.  A  method  by  which  a  hot  solution  of  ferrous  chloride 
with  common  salt  is  used  to  convert  copper  oxides  into  chlo- 
rides. This  is  the  Hunt  and  Douglas  method. 

The  Hunt  and  Douglas  process  of  extracting  copper  from 
its  ores  consists,  as  practised  in  North  Carolina  and  in  Chili, 
in  the  dissolving  of  the  oxides  in  a  hot  solution  of  proto- 
chloride  of  iron  and  common  salt,  thus  converting  the  proto- 
chloride  into  peroxide  of  iron,  and  the  oxide  of  copper  into 
protochloride  and  dichloride,  the  latter  of  which  is  soluble  in 
strong  brine.  From  this  solution  the  copper  is  precipitated 
by  the  introduction  of  scrap  iron.  This  method  involves 
almost  no  consumption  of  chemicals  other  than  common  salt, 
which  is  added  to  supply  unavoidable  losses.  The  sulphur- 
ous ores  are  converted  into  oxides  by  crushing,  grinding, 
and  calcination  in  three-hearthed  reverberatory  furnaces. 
The  iron  consumed  amounts  to  seventy  per  cent,  of  the 
copper  reduced  as  cement  copper.  One  furnace  roasts  two 
and  a  half  to  three  tons  of  ore  per  day,  using  one-third  cord 
of  wood. 

Special  cases. — Carbonate  ores  sometimes  supply  excel- 
lent copper,  although  rarely,  if  ever,  equal  to  that  found 
native.  They  are  now  smelted  in  cupola  furnaces,  in  which 
the  parts  exposed  to  highest  temperature  are  surrounded  and 
cooled  by  water-jackets.  These  furnaces  are  capable  of  smelt- 
ing 50  tons  per  day.  Oxides  are  similarly  smelted,  using  about 
I  ton  of  fuel  (coke)  for  6  or  7  tons  of  ore.  The  reduced  copper 
is  run  into  pigs  or  ingots  of  250  to  300  pounds  (115  to  160 
kilogs.,  nearly)  weight,  and  containing  2  or  2.5  per  cent.  slag. 

Sulphuretted  ores  are  smelted  both  in  reverberatory  fur- 
naces and  in  cupolas.  By  the  first  method,  the  ores  and 
slags,  containing  a  mean  of  about  33  per  cent,  copper,  are 
treated  in  charges  of  4  tons  each,  and  about  four  charges  are 
worked  in  24  hours.  The  matte  is  roasted  and  fused  until  a 
regulus  is  obtained  containing  70  per  cent,  copper.  This  is 
slowly  melted,  the  sulphur  oxidized  out  of  it,  the  slag 
skimmed  and  the  charge  oxidized  sufficiently  by  the  air- 


REDUCTION  OF  COPPER  ORES.  53 

blast  to  form  oxide  of  copper   and    sulphurous  acid  and  to 
produce  the  reactions, 

2  CuO  +  CuS  =  3Cu  +  SO, 
Cu+  SO. 


The  gases  thus  carry  some  sulphuric  acid.  The  metal 
should  finally  contain  over  95,  and  even  98,  per  cent,  copper. 
With  labor  at  $2.25  and  $1.50  per  day  and  coal  at  $4.00  per 
ton,  the  cost  of  reduction  is  about  $35  per  ton  of  copper  pro- 
duced. 

Cupolas  and  modifications  of  the  broad-mouthed  furnace 
of  Rachette  are  also  used  for  smelting  the  sulphuretted  ores, 
and  the  cost  is  thus  often  reduced  some  30  per  cent.  These 
furnaces  are  not  as  well  adapted  to  treating  a  wide  variety  of 
ore  as  the  reverberatory.*  The  latter  is  much  better  fitted 
than  the  former  for  smelting  arsenical  ores,  and  for  use 
where  wood  is  cheap,  and  charcoal,  coal  or  coke  expensive. 
The  slag  from  the  cupola  is  cleaner,  the  cost  of  repair  may  be 
made  less,  and  no  temporary  loss  of  copper  occurs  as  by  its 
permeation  of  the  bed  of  the  reverberatory. 

When  the  ore  is  very  lean,  or  contains  elements  difficult 
of  removal  by  smelting,  or  when  the  separation  of  silver  or 
other  valuable  metals  alloying  with  copper  is  necessary,  wet 
methods  of  reduction  are  practised.  The  copper  is  either 
separated  by  solution  or  by  separate  precipitation.  Such 
processes  are  adopted  to  save  the  metal  otherwise  lost  in 
mine  waters  either  below  ground  or  flowing  from  ore-heaps. 

Copper  reduced  by  the  dry  method  is  liable  to  consider- 
able injury  by  absorption  of  oxygen  while  in  fusion.  The 
extent  of  this  injury  is  well  shown  by  the  behavior  of  bars 
made  for  test  by  the  author  t  in  the  course  of  investigations 
of  the  properties  of  bronze  alloys. 

An  analysis  was  made  of  the  turnings  of  these  bars  for 
the  purpose  of  learning  whether  the  chemical  composition 
would  account  for  the  presence  of  blow-holes  and  the  lack  of 
ductility. 

*  "  Mineral  Resources  of  the  United  States."     J.  Douglas,  Jr.,  p.  270. 
f  Report  of  U.  S.  Board,  vol.  i.  ;  1878. 


54   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


The  result  was  the  discovery  of  an  extraordinary  amount  of 
suboxide  of  copper  in  bar  No.  I.  This  was  no  doubt  caused 
by  repeated  meltings. 

The  following  are  the  analyses : 


NO.   I. 

Per  cent. 

NO.   30. 
Per  cent. 

Metallic  iron                                     

O.O2O 

O   OIJ. 

0.014 

o  057 

Metallic  silver                                   

O   O15 

O   OI4. 

none 

none 

none 

none 

Metallic  tin                                               

none 

Metallic  bismuth      .  .      .      

none 

none 

Metallic  lead  

trace 

trace 

Metallic  copper                      .                

87.000 

06.  ^qo 

12.086 

•3.  ego 

Carbon  

none 

100.055 

99-995 

No.  30  had  been  less  exposed  to  the  air  than  No.  I  and 
less  frequently  remelted. 

34.  Metallic  Copper,  although  both  malleable  and  duc- 
tile, excels  in  the  first  quality  and  finds  more  frequent  em- 
ployment in  the  form  of  sheet  metal  than  in  that  of  wire. 
These  qualities  are  possessed  in  the  highest  degree  by  the 
pure  metal  and  are  greatly  impaired  by  very  slight  admixture 
of  foreign  elements  of  metallic  alloy.  Its  tenacity  and  hard- 
ness, although  less  than  that  of  iron  or  steel,  is  greater  than 
that  of  any  other  non-ferrous  material ;  and  its  power  of 
resisting  oxidation,  of  taking  a  fine  polish  and  of  easy  work- 
ing, make  it  an  extremely  valuable  material  to  the  engineer. 

Good  copper  should  have  a  strength  of  at  least  30,000 
pounds  per  square  inch  (2,109  kg-  per  sq.  cm.)  ;  and  cold-work- 
ing, by  wire-drawing,  for  example,  raises  its  tenacity  some- 
times to  double  that  amount.  If  worked  hot  in  the  presence 
of  oxygen,  it  is  liable  to  serious  injury  by  internal  oxidation, 
and,  in  presence  of  carbon,  by  the  formation  of  the  carbide. 
It  becomes  hard  and  brittle  when  hammered  or  wire-drawn, 


COPPER   OF  COMMERCE.  55 

and  its  ductility  is  restored  by  annealing,  by  sudden  cooling — 
the  opposite  of  the  treatment  required  in  annealing  steel. 

It  can  be  forged,  when  pure,  either  hot  or  cold,  more 
easily  than  iron.  It  loses  strength  with  increasing  tempera- 
ture. Its  oxide  and  carbonate  are  poisonous,  and  its  surface 
is  therefore  tinned  when  it  is  used  for  culinary  purposes  or 
where  liable  to  serious  injury  by  corrosion. 

Copper  is  very  seldom  cast,  unalloyed,  in  consequence  of 
the  difficulty  of  obtaining  sound,  strong  castings.  When 
fluxed  with  phosphorus,  it  is,  however,  possible  to  make 
castings  of  good  quality ;  and  that  metalloid  is  one  of  the  best 
known  fluxes  for  all  its  alloys.  "  Phosphorus-copper  "  has  a 
strength,  according  to  Abel,  of  from  30,000  to  50,000  pounds 
per  square  inch  (2,103  to  3>5X5  kgs.  per  sq.  cm.),  as  the  per- 
centage of  phosphorus  added  rises  from  one  to  three  or 
four  per  cent. 

Riche*  found  that  the  density  of  copper,  subjected  alter- 
nately to  mechanical  action,  then  to  tempering  or  annealing, 
displays  inverse  variations  according  as  it  is  exposed  to  the 
air  or  sheltered  from  it  during  the  re-heating ;  while  in  the 
first  case  the  mechanical  action  increases  the  density,  in  the 
second,  mechanical  action  diminishes  it. 

Professor  Farmer  has  informed  the  author  that  he  has 
succeeded  in  depositing  copper,  from  cyanide  solutions  by 
electrolytic  processes,  harder  than  untempered  steel. 

35.  Copper  of  Commerce.  —  The  copper  found  in  the 
market  is  of  several  kinds,  each  known  commercially  by  a 
different  name. 

"  Lake  Copper  "  is  that  obtained  in  the  neighborhood  of 
Lake  Superior,  and  is  principally  native  copper.  It  is  remark- 
ably pure,  and  when  well  handled  in  melting  and  poling,  it  is 
considered  unexcelled  for  purposes  as,  for  example,  con- 
ductors of  electricity,  in  which  every  trace  of  foreign  matter 
reduces  appreciably,  and  often  seriously,  the  value  of  the 
copper.  The  best  Lake  copper  has  ninety-three  per  cent,  of 
the  conductivity  of  chemically  pure  copper. 

Australian,  South  American,  and  European  coppers  are 

*  Comptes  Rendus,  vol.  55,   1862  ;  pp.  143-7, 


56  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

usually  not  native  coppers,  nor  are  the  coppers  obtained 
from  nearly  every  other  part  of  the  world.  Japanese  copper 
is  a  richly  colored  metal,  which  comes  into  the  market  in 
small  ingots.  All  commercial  coppers  obtained  from  other 
than  deposits  of  native  copper  are  likely  to  be  contaminated 
by  the  presence  of  arsenic,  sulphur,  oxygen,  and  alloyed  with 
lead,  tin,  iron,  nickel,  bismuth,  silver,  and  antimony,  of  which 
sulphur,  oxygen,  and  antimony  are  most  troublesome. 

Copper,  as  sold  in  the  market,  contains  from  one-tenth  to 
one  per  cent,  of  foreign  matter ;  an  excellent  sample  con- 
tained 99.9  per  cent,  copper.  One-tenth  of  one  per  cent,  of 
impurity,  according  to  Egleston,'*  may  reduce  the  conduc- 
tivity of  the  metal  ten  per  cent.  The  presence  'of  one-half 
per  cent,  may  make  the  metal  worthless  for  many  purposes. 
The  following  are  analyses  of  three  samples :  f 


AMERICAN    COPPER. — EGLESTON. 


ORE    KNOB. 

L.   SUPERIOR. 

BALTIMORE. 

Metallic  copper       .        . 

QQ.  80 

QQ.83 

QQ.61^ 

Oxygen  

O.  1Q 

o.  15 

O.OO 

Sulphur  

O.OO 

O.OO 

O.OO 

Silver  

o.o^ 

0.026 

0.066 

Lead  

O.OI 

0.016 

0.044 

O.OO 

O.OO 

0.088 

Antimony  

O.OO 

O.OO 

o.o^c; 

Silver  in  2,000  pounds 

100.25 
14.  6 

IOO.O2 

7  '•  °3 

99.893 

IQ.  7^ 

A  sample  of  Swiss  copper,  found  by  Berthier  \  topossess 
extraordinary  softness,  ductility,  and  malleability,  was  com- 
posed of 


Copper 99 . 12 

Potassium o.  38 


Calcium 0.33 

Iron 0.17 


and  that  author  concludes  that  its  valuable  properties  are 

*  Trans.  Inst.  Min.  Engineers,  vol.  x.,  p.  63. 

t  Ibid.,  p.  54. 

\  ' '  Essais  par  la  Voie  Seche. " 


COPPER  OF  COMMERCE.  57 

due  to  the  presence  of  the  alkaline  metals.  Mallet  proposes* 
to  introduce  an  alloy  of  sodium  and  tin  in  the  manufacture 
of  gun-bronze  to  secure  freedom  from  oxide,  using  0.05  per 
cent,  sodium,  or  less. 

Copper  is  too  soft,  and  usually  too  weak,  to  be  of  as  great 
value  in  the  arts  as  iron,  even  were  its  price  to  admit  of  such 
use.  It  is  principally  employed  in  the  form  of  sheets  and 
wire.  Copper  in  heavy  sheets  is  sometimes  used  for  the 
"fire-boxes"  of  locomotives,  where  iron  would  be  rapidly 
corroded  ;  it  is  extensively  used  in  making  large  vessels  for 
manufacturers  of  chemicals  and  pipes.  Copper  pipes  of 
large  size,  such  as  are  used  on  marine  engines  for  steam  and 
feed  pipes,  are  made  by  rolling  up  sheet  copper  and  brazing 
the  edges  together.  Small  pipe  is  sometimes  drawn  to  size 
in  dies  ;  feed  and  "  blow-off "  pipes  are  usually  thus  made  ; 
this  "  solid-drawn  "  pipe  is  more  costly,  but  much  better,  than 
bra/ed  pipe." 

The  ductility,  malleability,  and  the  considerable  strength 
of  copper,  permitting  its  being  worked  into  rods,  bars,  wire, 
or  sheets  with  equal  facility,  make  it,  next  to  iron,  the  most 
useful  of  the  metals.  Its  quality  is  so  greatly  dependent 
upon  its  purity  and  freedom  from  oxidation  or  admixture 
with  other  metals,  that  it  is  very  important  to  the  engineer 
to  see  proper  precaution  observed  in  obtaining  it  for  struct- 
ural purposes. 

Working  by  the  hammer,  in  the  rolls,  or  in  the  wire-mill, 
causes  great  increase  in  tenacity,  while  carelessness  in  melt- 
ing and  casting  it  may  render  it  worthless  for  the  purposes 
of  the  engineer,  and  even  the  strengthening  processes  cannot 
be  carried  far  except  with  occasional  annealing.  It  may  be 
worked  either  cold  or  hot,  and  forged  like  iron,  if  not  so 
highly  or  so  long  heated  as  to  cause  serious  oxidation.  It 
oxidizes  quickly  at  high  temperatures,  and  also  when  exposed 
to  a  damp  atmosphere.  Fusing  it  under  a  layer  of  salt,  it  is 
less  liable  to  injury  in  the  foundry. 

Thin  sheet  copper  is  subject  to  a  peculiar  deterioration 
of  strength,  with  time,  which  has  been  studied  but  little,  and 
*  "  Construction  of  Artillery,"  p.  97. 


58    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

the  cause  of  which  is  not  fully  ascertained.  This  degrada- 
tion of  quality  is  singularly  irregular  and  erratic,  and  affects 
the  product  of  the  best  mills,  as  well  as  low  grade  copper. 
It  has  been  noticed  particularly  in  thin  metal,  as  cartridge 
sheets.  This  metal  is  sometimes  of  nearly  pure  copper,  but 
often  of  alloy  with  zinc  in  considerable  amount.  Cartridge 
metal,  passing  the  severest  tests,  was  reported  by  Capt. 
Michaelis  as  failing  in  firing ;  later  an  improvement  was 
observed.  Dr.  Egleston  attributed  failure  in  such  cases  to 
several  causes,  as  impurities  in  the  copper,  oxidation,  over- 
heating, underheating,  and  over-compression  in  the  rolling 
mill.  Large  quantities  of  gas  are  sometimes  separated  from 
the  metal,  often  many  times  its  own  bulk.  The  stress  and 
flow  caused  by  the  presence  of  this  gas  may  be  the  most 
usual  cause  of  loss  of  strength  with  time. 

Copper  is  rarely  worked  in  the  lathe  or  by  cutting  tools  ;  it 
is  soft,  yet  tough  and  tenacious,  and  is  easily  distorted  by  the 
resistance  offered  to  the  tool,  which  it  clogs  and  causes,  espe- 
cially if  the  latter  is  sharp  and  has  an  acute  cutting  angle,  to 
chatter  and  dig  into  the  work.  Its  peculiar  qualities  fit  it  well 
for  working  with  the  hammer,  and  it  is  often  forged  hot,  and 
still  oftener  worked  cold.  Pieces  are  often  cast  and  then 
hammered  into  the  desired  form,  or  beaten  to  the  required 
degree  of  thinness.  If,  during  the  process,  the  metal  becomes 
too  hard  and  brittle,  it  is  annealed  by  heating  and  suddenly 
cooling  it. 

Joints  are  made  either  by  "  brazing  "  or  "  hard-soldering  " 
with  an  alloy  of  copper  rich  in  zinc,  by  rivetting,  or  by  soft- 
soldering  with  an  alloy  of  tin  and  lead. 

Copper  vessels  are  usually  brazed,  and  when  used  for 
culinary  purposes,  or  when  liable  to  be  filled  with  alkalies  or 
other  substances  which  may  dissolve  the  metal,  are  tinned. 
This  operation  consists  in  first  thoroughly  cleaning  and 
brightening  the  surface  by  scraping  or  sand-papering,  then 
washing  with  a  solution  of  sal-ammoniac,  or  of  zinc  in  hydro- 
chloric acid,  which  leaves  a  clean  metallic  surface,  free  from 
oxide  and  greasy  matter.  Tin  is  then  melted  in  the  vessel 
and  rubbed  over  the  whole  interior,  the  surplus  finally  poured 


SHEET  COPPER. 


59 


off,  and  the  polishing  completed.  Oily  and  ammoniacal 
matters,  and  according  to  Sir  Humphrey  Davy,  weak  solu- 
tions of  salt,  attack  copper,  as  do  nearly  all  acids. 

36.  Sheet  Copper  was  formerly  much  used  by  engravers, 
but  has  been  much  less  generally  called  for  by  that  trade 
since  other  engraving  processes  have  been  perfected.  En- 
graved rolls  for  calico-printing  often  have  their  surfaces  made 
of  the  finest  sheet  copper,  but  are  sometimes  made  of  the 
cast  metal.  Embossing  cylinders  are  made  of  copper  or  gun- 
metal.  The  patterns  are  produced  either  by  engraving  or  by 
stamping. 

Sheet  copper  is  used  to  some  extent,  but  less  than  for- 
merly, in  lining  air-pump  cylinders  for  steam  engines  and 
pumps  used  in  mines,  where  the  water  is  found  to  seriously 
corrode  iron  ;  but  here,  as  in  .sheathing  ships,  alloys  with  tin 
or  zinc  have  displaced  the  unalloyed  metal. 

The  sheet  copper  found  in  the  market  is  classed  as  Bra- 
zier's Sheets  and  Sheathing  Copper.  The  sizes  of  the  sheets 
are : 

SIZES   AND   WEIGHTS   OF    SHEET    COPPER. 


BREADTH. 

LENGTH. 

WEIGHT. 

Brazier's 

2  feet 

4  feet. 

5  to   25  Ibs.  per  sheet. 

Sheathing    

2*    " 

3     " 
4 
14  inches. 

5     " 

5     " 
6     " 
48  inches. 

9  to  150      "         " 
1610300      "         " 
16  to  300      " 
14  to    34  oz.  per  sq.  ft. 

The  weight  may  be  approximately  computed  by  multiply- 
ing the  cubic  contents  of  the  mass  in  inches  by  0.32 12  to 
obtain  the  weight  in  pounds. 

The  thickness  of  sheet  copper  is  often  measured  by  wire- 
gauge,  and  the  diameter  of  copper  wire  is  always  so  meas- 
ure d. 

Copper  is  used  to  some  extent  in  electro-plating,  and  is 
of  common  use  with  a  slight  alloy  of  hardening  metal  in 
coinage  ;  sheet  copper  is  often  tinned.  Nearly  all  the  copper 


60  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

used  in  the  arts,  however,  is  alloyed  with  zinc  and  tin  to  form 
the  brasses  and  bronzes. 

When  used  unalloyed,  specifications  should  call  for  a 
tenacity  of  at  least  25,000  pounds  per  square  inch  in  castings, 
35,000  in  bars,  and  60,000  in  wire  (5,075,  7,105,  and  4,218 
kgs.  per  sq.  cm.). 

Copper  wire  is  used  in  enormous  quantities  in  the  con- 
struction of  electric  and  magnetic  apparatus.  Its  great 
conductivity,  which  is  six  times  that  of  iron,  makes  it  pecu- 
liarly valuable  for  this  purpose.  Its  greater  conductivity  for 
heat,  also  excelling  iron  two  and  a  half  times,  has  given  it 
value  for  heating  surfaces  of  steam  boilers.  Copper  "  fire- 
boxes "  are  often  used  in  locomotives,  and  copper  utensils 
are  of  frequent  use  in  minor  departments  of  engineering,  as 
in  distillation,  and  in  chemical  and  culinary  operations.  It 
is  used  to  some  extent  in  the  sheathing  of  wooden  vessels ; 
but  one  of  its  alloys,  a  special  sheathing  metal,  has  now. 
nearly  taken  its  place.  The  "  fastenings  "  of  wooden  ships 
are,  in  the  best  practice,  always  made  of  copper;  it  oxidizes 
very  slowly,  and  its  oxide  does  not  injure  the  timber  through 
which  it  is  driven.  Its  use  unalloyed  is  far  less  extensive, 
however,  than  when  alloyed  with  other  metals. 

The  steam  and  feed-water,  and  other  pipes  used  on  ship- 
board and  on  locomotives,  are  often  made  of  copper,  as  are 
the  staybolts  of  heating  surfaces  when  the  latter  are  made  of 
this  metal.  Sheet  copper  is  rolled,  for  fire-boxes  and  other 
purposes,  up  to  10  feet  10  inches  (3.3  metres)  long.  These 
sheets  must  be  free  from  cracks,  blow-holes,  or  scale  ;  and  to 
secure  a  good  surface,  the  sheets  are  inspected  while  going 
though  the  rolling  mill,  and  any  defects  detected  are  carefully 
removed  by  the  chisel,  or  by  scraping,  before  the  finishing 
pass  is  given.  It  is  even  necessary,  frequently,  to  plane  the 
ingots  before  rolling  them. 

Fire-box  tube-sheets  are  hammer-hardened,  in  order  that 
the  "  expander  "  used  in  setting  the  tubes  may  not  distort 
the  sheet.  Hammer-hardened  copper,  when  tested  by  ten- 
sion, stretches  irregularly,  and  the  hammer-hardened  plate  may 
thus  be  distinguished  from  plate  not  so  treated ;  the  effect  is 


COMMERCIAL    COPPER.  6 1 

also  seen  in  the  diminished  elongation  without  much  change 
of  tenacity.  Moderate  hammering,  according  to  Lebasteur, 
is  quite  as  effective  as  more  severe  work. 

Copper  rods,  or  bars,  are  made  with  the  same  care,  and 
the  same  precautions  are  adopted,  as  in  making  sheet  copper. 
If  reduced  by  the  wire-drawing  process,  the  reduction  must 
be  small  at  each  pass,  and  the  metal  should  be  occasionally 
annealed,  if  the  reduction  is  considerable.  The  maximum 
reduction  in  diameter  should  not  exceed  -j^th  inch  (0.16  centi- 
metre). Rods  intended  for  fire-box  stays  are  often  drilled 
through  the  axis  of  the  stay,  as  a  means  of  detecting  fracture  ; 
these  stays  are  now  sometimes  made  by  rolling  up  heavy 
sheet  copper  on  a  mandril  and  then  drawing  to  size. 

Copper  tubes  and  pipe  are  sometimes  made  by  repeatedly 
stamping  disk-shaped  ingots  under  the  hydraulic  press,  and 
thus  gradually  changing  their  form  to  that  desired.  Very 
large  quantities  of  copper  are  used  in  coinage. 

The  consumption  of  copper  in  the  United  States  is  not 
far  from  40,000  tons  per  annum,  and  a  very  nearly  equal 
amount  is  used  in  Great  Britain  (2.8  Ibs.  per  capita). 

Copper  is,  when  cast,  rendered  sound  and  strong  by  the 
use  of  phosphorus  as  a  flux.  Abel,  in  1860,  found  that 
the  introduction  of  2  to  4  per  cent.*  produces  a  remarkably 
uniform,  sound,  dense  and  tough  metal,  exceeding  the 
strength  of  ordinary  gun  bronze  by  one-half,  and  attaining  a 
tenacity  of  50,000  pounds  per  square  inch  (4,218  kilogs.  per 
sq.  cm.) 

Alloyed  with  tin  to  form  bronze,  and  with  zinc  to  make 
brass,  copper  has  extensive  use  in  all  the  constructive  arts. 
It  is  used  in  alloying  gold  and  silver  for  coinage,  plate,  and 
other  similar  purposes  for  which  those  metals  are  too  soft. 
The  copper  usually  amounts  to  about  ten  per  cent,  of  the 
total  weight. 

COPPER  TELEGRAPH  WIRE,  as  stated  by  Glover  &  Co.,  has 
weight  and  conductivity,  if  pure,  as  follows  : 

*  Construction  of  Artillery  ;  Inst.  Civil  Engineers,  1860. 


62   MATERIALS  CF  ENGINEERING— NON-FERROUS  METALS. 


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64  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

37.  Tin  (Si 'annum  ;  Sn.)  is  less  widely  and  less  plentifully 
distributed  than  copper,  but  has  probably  been  as  long  known 
and  as  generally  used.     In  fact,  the   two  metals  have  always 
been,  as  they  are   to-day,  almost  invariably   used   together ; 
and  their  alloys,  the  bronzes,  have  been  in  general  use  since 
the  earliest  times.     The   ores  of  tin  are  found   and  worked 
extensively  in  Devonshire  and  Cornwall,  Great  Britain,  and 
less  extensively  in  Malacca,  Banca,  Germany,  and  Australia, 
in  small  quantities   at  Ashland,  Alabama,  and  lately  in  the 
Black  Hills  of   Dakota.      Banca  tin   usually  commands  the 
highest  price  ;  it  is  known  in  the  market  as  "  Straits  Tin." 

Tin  is  found  as  u  stream  tin  "  (cassiterite)  in  many  parts 
of  the  United  States  which  are  underlaid  by  the  primitive 
rocks,  and  the  ores  are  found  in  small  quantities  in  California 
and  other  States  west  of  the  Mississippi,  in  Maine,  and  in 
Alabama.  It  is  only  worked  at  Ashland,  and  in  a  few  other 
localities  scattered  over  the  United  States.  The  tin  used 
in  the  United  States  comes  principally,  via  Great  Britain, 
from  Banca,  Billiton,  Cornwall,  Australia,  and  South  Amer- 
ica. The  amount  is  above  10,000  tons  annually. 

Tin  sometimes  occurs  in  the  metallic  state,  but  is  gen- 
erally found  as  an  oxide. 

38.  Ores,  and  Processes  of  Reduction. — The  common  ore 
of  tin,  cassiterite,  stannite,  stannic  oxide,  Sn  O2,  is  a  dioxide, 
and  is  often  called  tin-stone  or  stream-tin.     The  ore  usually 
contains  between  65  and   75   per  cent,  metal.     It  occurs  in 
veins  traversing  the  primitive  rocks.     Much  care  is  demanded 
in    dressing   it,  and    in    assorting   it    into  the  four  qualities 
usually  classed  at  the  mine.     The  ore  is   stamped,  washed, 
weathered  a  few  days,  calcined,  again  weathered  and  washed, 
and  finally  smelted  in  reverberatory  furnaces.     The  tin  thus 
obtained  requires  refining,  which  is  done  as  in  the  working 
of  copper,  the  melting  and  poling  demanding  and  occupying 
five  or  six  hours,  and  yielding  a  very  pure  metal.     The  blast- 
furnace is  sometimes  used  instead  of  the  reverberatory,  and 
is  said  to  yield  a  purer  tin. 

In  detail,  the  processes  of  preparation  are  as  follows : 
The  oxide  comes  to  the  metallurgist  as  "  tin-stone,"  or 


PRODUCTION  OF  TIN.  65 

oxide,  either  as  "  stream  tin  ore,"  called  often  "  alluvial  ore," 
or  "  mine  tin  ore."  The  former  is  usually  comparatively 
clean.  The  latter  is  washed,  to  free  it  from  the  earthy  mat- 
ters accompanying  it,  by  stirring  it  on  a  grating  under  a 
flowing  stream ;  it  is  then  assorted  carefully,  the  stony  and 
useful  part  picked  out  and  thrown  away,  the  remainder 
broken,  if  in  large  pieces,  and  reduced  to  a  sufficiently  small 
size  to  work  well  under  the  stamps. 

The  stamps  consist  of  a  series  of  heavy  blocks  of  wood 
shod  with  cast  iron,  usually  weighing  225  pounds  (102  kilo- 
grammes) or  more,  mounted  on  the  lower  ends  of  vertical 
shafts.  They  are  lifted  by  cams  revolving  on  a  horizontal 
shaft,  which  engage  lugs  secured  to  the  vertical  rods.  The 
motive  power  is  either  water  or  steam,  and  the  stamps  make 
fifteen  to  twenty-five  blows  per  minute.  The  stamps  fall 
into  a  trough  into  which  the  ore  is  fed,  and  as  it  is  pulverized 
by  the  blows  it  is  washed  out  at  the  side,  through  a  finely 
perforated  screen,  by  a  constantly  flowing  stream  of  water. 

From  the  stamps,  the  fine  ore  is  carried  by  the  current  to 
a  succession  of  settling  tanks,  in  which  it  collects,  while  all 
other  and  lighter  matter  is  swept  away.  The  "  slimes  "  thus 
retained  are  removed,  are  again  washed  in  a  flowing  stream 
of  water,  and  are  then  sent  to  the  calcining  furnaces.  These 
are  reverberatory  furnaces,  in  which  the  sulphur  and  arsenic 
are  driven  out  of  the  pyrites  with  which  the  ore  is  usually 
contaminated.  The  addition  of  common  salt  aids  in  this 
process,  by  the  production  of  vaporous  chlorides. 

The  ore  is  now  washed  once  more  to  remove  the  sulphate 
of  copper  which  exists  in  the  mass,  and  often  still  again  to 
free  it  from  oxide  of  iron  and  other  lighter  mineral  matters, 
leaving  the  "  black  tin  "  in  proper  shape  for  smelting. 

The  smelting  process  is  conducted  in  reverberatory  fur- 
naces similar  in  general  form  and  method  of  working  to  those 
used  in  iron  working.  The  charge  of  ore,  now  containing 
about  sixty  per  cent,  tin,  and  weighing  a  ton  or  more,  includ- 
ing about  twenty  per  cent,  its  weight  of  ground  coal  and 
lime,  introduced  as  a  flux  to  remove  the  silica,  is  dampened 
with  a  small  quantity  of  water  and  spread  upon  the  hearth. 
5 


66  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

At  a  low,  and  long-continued  heat,  the  oxide  of  tin  gradually 
becomes  deoxidized  by  the  carbon  present,  and  the  metallic 
tin  settles  in  the  middle  of  the  furnace,  the  hearth  being 
slightly  dished  to  receive  and  retain  it.  The  ore  is  contin- 
ually stirred  as  this  goes  on,  to  facilitate  the  settling  of  the 
tin  ;  while  the  heat  is  finally  considerably  raised  to  produce 
a  fluid  slag.  The  slag  is  finally  removed,  and  the  tin  is  run 
off  into  a  reservoir,  from  which,  after  the  dross  has  risen  to  its 
surface  and  been  skimmed  off,  the  metal  is  cast  in  ingots.  A 
portion  of  the  slag  is  sufficiently  rich  in  tin  to  be  re-worked. 

The  ingots  of  tin,  made  as  above,  are  refined  by  re-melting 
and  separation  from  the  dross,  and  then  "  boiling"  in  a  large 
refining  basin,  kept  at  a  moderate  temperature,  somewhat 
above  that  of  fusion,  by  a  process  resembling  in  principle  the 
"  poling"  of  copper.  The  wood  is  secured  in  the  bottom  of 
the  tank  under  the  tin,  and  the  steam  and  gases  rising  from 
it  as  it  chars  beneath  the  molten  tin,  cause  the  foreign 
materials  to  separate  and  rise  to  the  surface. 

This  process  being  completed,  the  tin  is  again  cast  in 
ingots ;  the  quality  of  the  metal  being  determined,  not  only 
by  the  extent  to  which  the  purification  has  been  carried,  but 
on  the  part  of  the  pool  from  which  the  ingot  is  cast.  The 
upper  part  is  purer  than  the  lower,  and  yields  "  refined  tin," 
while  the  lower  portion  is  ordinary  "  block  tin  "  ;  they  should 
contain  from  0.985  to  0.998  pure  tin.  The  lowest  part  of  the 
molten  mass  in  the  basin  is  reserved  for  further  refining. 

A  small  blast-furnace  is  sometimes  used,  as  in  Saxony,  in 
reducing  the  ore  ;  but  it  is  a  wasteful  process.  The  fuel  is 
charcoal,  and  the  flux  is  either  siliceous  or  calcareous,  accord- 
ing as  the  ore  contains  an  excess  of  basic  or  acid  constit- 
uents. 

39.  Commercial  tin  is  never  pure.  Chemically  pure  tin 
has  a  specific  gravity  of  7.28  to  7.4,  according  to  the  method 
of  preparation,  the  purest  being  lightest.  Its  atomic  weight 
is  116;  color  white,  with  a  tinge  of  yellow;  it  possesses  a 
peculiar  odor;  it  oxidizes  with  difficulty,  and  when  bent 
emits  the  crackling  sound  known  as  the  "  cry  of  tin."  It  has 
little  tenacity,  considerable  ductility,  and  greater  malleability. 


COMMERCIAL    TIN. 


67 


The  coefficient  of  expansion  is  0.000023  ;  its  melting  point  is 
443°  Fahr.  (232°  Cent.) ;  specific  heat,  0.0562  ;  latent  heat  of 
fusion,  14.25.  It  boils  at  a  white  heat ;  its  conductivity  is  low. 

Tin  oxidizes  very  slowly  in  the  air  at  ordinary  tempera- 
tures, but  burns  quite  freely  at  a  white  heat  and  with  a  white 
flame.  Exposed  to  severe  cold  it  becomes  crystalline  and 
friable.  Its  principal  uses  are  in  the  making  of  alloys  with 
copper,  zinc,  lead,  etc.,  and  in  the  manufacture  of  "tin-plate." 

The  yellow  oxide  is  used  for  polishing  metals,  such  as 
steel  cutlery  and  glass.  The  white  oxide  is  used  in  making 
a  white  opaque  glass  generally  known  as  "  enamel." 

This  metal  is  readily  rolled  into  very  thin  sheets,  known 
as  tin-foil,  and  drawn  into  tubes  and  into  fine  wire.  It 
resembles  zinc  in  its  change  from  great  ductility  at  the  boil- 
ing point  of  water,  to  equal  brittleness  at  about  400°  F. 
(204°  C).  It  then  melts  a  few  degrees  above  the  latter  tem- 
perature, as  already  stated. 

The  following  is  a  complete  analysis,  made  at  the  request 
of  the  Author,  of  Queensland  tin  : 


ANALYSIS   OF    "QUEENSLAND   TIN. 

Per  cent.  I 

Lead o.  165 

Iron 0.035 

Manganese 0.006 

Arsenic trace. 

Copper none. 

Zinc.. 


Per  cent. 

Antimony none. 

Bismuth " 

Nickel " 

Cobalt " 

Tungsten " 

Molybdenum " 


Kerl  *  gives  a  set  of  analyses,  thus  : 


KIND. 

BANCA. 

BRITISH. 

PERUVIAN. 

SAXON. 

BOHEMIAN. 

Elements.  .  .  . 
Tin  

I 
99.961 

o  019 
0.014 
0.006 

2 

99.9 
0.2 

I 
99.96 

2 
98.64 

I 

93-50 
O.O7 
2.76 

2 

95-66 
0.07 
1-93 

99.9 

I 

99-59 

2 
98.18 

Iron   .  . 

Lead  
Copper  

0.24 

0.20 

o.  16 



0.406 

"1.60 

3-76 

2-34 

*  Metalnuttenkunde,  1873. 


68   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Grain  tin  is  made  by  heating  ingots  to  a  temperature  at 
which  they  become  brittle  and  breaking  them  up  by  dropping 
them  on  the  floor. 

MANUFACTURED  TIN  is  found  in  the  market  in  nearly 
every  form  in  which  iron  and  copper  are  sold. 

Tin-foil  is  made  by  rolling  into  plates  and  sheets,  then 
heating,  doubling,  and  again  rolling,  and  repeating  the  latter 
processes  until  it  is  sufficiently  thin  for  use  as  desired.  It  is 
sometimes  rolled  down  in  a  compound  sheet  composed  partly 
of  lead  ;  and  it  is  often  alloyed  with  lead  to  make  thin  sheets 
and  other  forms.  Tin-plate  is  made,  as  described  in  the 
preceding  volume,  by  tinning  sheet-iron,  and  consists  prin- 
cipally of  the  latter  metal.  Copper,  lead,  and  zinc  are  some- 
times tinned.  Brass  pins  are  tinned  by  dipping  in  a  solution 
of  the  chloride  or  of  the  oxide ;  the  other  metals  are  some- 
times similarly  tinned. 

Unmanufactured  tin  comes  into  the  market  as  "  block 
tin,"  as  "  grain  "  tin,  and  in  small  bars  or"  sticks."  Block  tin 
is  cast  in  ingots  or  blocks  in  moulds  of  marble ;  grain  tin  is 
made  by  heating  these  ingots  until  very  brittle,  and  then 
breaking  them  up  on  stone  blocks  ;  it  is  sometimes  granulated 
by  melting  and  pouring  into  water. 

The  production  of  tin  has  been  enormously  increased 
during  late  years  by  the  increased  demand  for  tin-plate,  which 
is  due  to  the  growth  of  the  "  canning  industries  "  and  the 
roofing  business.  The  consumption  now  exceeds  a  quarter 
of  a  million  tons  per  year. 

Sheet  tin,  or  tin-foil,  is  often  no  more  than  one-thousandth 
of  an  inch  (0.00254  cm.)  in  thickness.  The  foil  is  used  for 
wrapping  tobacco  and  other  materials  which  are  to  be  pro- 
tected from  the  action  of  the  atmosphere.  Thicker  sheets 
are  used  in  "  silvering  "  mirrors  by  amalgamation  with  mer- 
cury, and  for  making  amalgam  and  for  other  purposes  con- 
nected with  the  generation  and  use  of  electricity.  Pure  tin 
is  used  in  making  some  tin  vessels,  as  dyers'  kettles.  Its 
cleanliness  and  innocuous  qualities  make  it  valuable  for  tin- 
ning culinary  utensils.  The  tubes  are  used  sometimes  alone, 
and  often  as  a  lining  for  lead  pipe,  in  the  supply  of  water  to 


ZINC.  69 

houses.  The  wire  is  very  ductile  and  moderately  tenacious, 
and  has  the  perfect  inelasticity  exhibited  by  tin  in  all  its 
forms. 

Tin  is  very  extensively  used  alloyed  with  lead,  in  pewter 
and  Britannia  metal,  and  sometimes  with  a  little  copper  as  a 
hardening  or  "temper." 

The  evidence  lately  discovered  of  the  existence  of  an 
extensive  region,  bearing  tin,  in  Dakota,  according  to  the 
report  of  Professor  Blake,*  and  of  other  deposits  in  Ala- 
bama, lead  to  the  expectation  of  a  large  future  development 
of  this  industry  in  the  United  States. 

Of  the  whole  product  of  the  world,  over  15,000  tons  per 
annum  are  used  in  Great  Britain,  probably  nearly  as  much  in 
the  United  States.  Cornwall  supplies  above  10,000  tons  per 
annum,  Banca  is  producing  large  quantities,  and  Australia  is 
rapidly  approaching  that  district  in  its  production.  The  use 
of  tin  for  "  tin-plates  "—sheet  iron  tinned  on  both  sides — is  a 
very  great  proportion  of  the  total.  Good  "  tin-plate "  is 
plated  with  the  best  tin,  while  the  cheaper,  or  "terne,"  plates 
are  plated  with  cheap  alloy.  Good  tin-plate  is  distinguished 
by  the  thickness,  evenness,  and  brightness  of  the  coating  of 
tin,  the  absence  of  dark  spots  produced  by  imperfections  in 
the  coating  and  of  roughness  due  to  the  incomplete  covering 
of  the  rough  iron  surface.  "  Pin-holes  "  in  the  coating  often 
indicate  a  low  grade  of  iron  in  the  plated  sheet.  The  iron 
should  be  good  "  charcoal  iron,"  but  in  often  "  coke  iron." 
The  cheaper  grades  are  as  suitable  for  many  purposes  as  the 
more  expensive. 

40.  Zinc  in  the  metallic  state  was  not  familiar  to  the 
ancients,  although  they  were  accustomed  to  use  its  ores  in 
the  manufacture  of  brass.  The  alloy  was  used  in  coins  occa- 
sionally ;  the  Greek  and  Roman  coinage  was,  however,  prin- 
cipally bronze.  Zinc  was  probably  discovered,  five  hundred 
years  ago,  by  Albertus  Magnus,  and  by  him  called  marchasita 
aurea  ;  its  modern  name  was  first  given  by  Paracelsus  in  the 
middle  of  the  sixteenth  century.  It  became  a  regular  article 
of  manufacture  about  1720,  in  Germany,  and  in  England 

*  Engineering  and  Mining  Journal,  1883. 


7O  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

fifteen  or  twenty  years  later ;  the  ore  generally  reduced  was 
calamine,  and  the  process  was  one  of  distillation.  The 
metal  had  already  been  smelted  in  the  East  Indies.  It  has 
been  regularly  manufactured  in  the  United  States  since  about 
1850,  first  at  Bethlehem,  N.  J.,  and  later  in  a  number  of  other 
localities.  The  city  of  St.  Louis,  alone,  supplies  the  market 
with  fifteen  tons  per  day.  The  whole  product  for  the  United 
States  was,  in  1888,  about  60,000  tons  (or  tonnes,  nearly). 

Zinc  ores  were  known  to  the  ancients,  and  were  used  in 
the  manufacture  of  brass  long  before  the  art  of  reducing 
them  was  discovered.  The  alloy  was  made  by  smelting 
together  the  ores  of  copper  and  zinc.  The  metal  became 
known  about  1600,  but  was  little  noticed  until  after  Hobson 
and  Sylvester  discovered,  in  1805,  that  it  becomes  ductile 
and  malleable  at  about  300°  F.  (144°  C.),  when  it  was  brought 
into  the  market  in  competition  with  lead.  It  has  since  been 
extensively  used  for  sheathings,  roofing,  culinary,  and  other 
vessels,  architectural  ornaments,  etc.  The  oxide  is  exten- 
sively used  as  a  substitute  for  white  lead. 

41.  Ores  of  Zinc  occur  abundantly  in  the  United  States, 
the  best  being  obtained  in  New  Jersey,  Pennsylvania,  and 
Virginia,  and  in  a  line  of  deposits  running  through  West 
Virginia  and  the  Middle  States,  across  to  Illinois,  Missouri, 
and  Kansas,  and  north  into  Wisconsin.  Large  quantities  are 
mined  in  Missouri  and  other  parts  of  the  country.  They  are 
mined  extensively  in  Europe.  Calamine  and  blende  are  the 
ores  principally  used  in  the  production  of  the  zinc  of  com- 
merce. 

These  ores  are  the  carbonate  known  as  calamine,  the  sili- 
cate, or  siliceous  calamine,  the  sulphide,  or  blende,  and  the 
oxide,  or  red  ore. 

The  latter  is  given  its  color  by  the  oxides  of  manganese 
and  iron  which  are  present  with  the  zinc.  It  is  the  common 
ore  of  New  Jersey.  Calamine  is  also  found  in  the  United 
States,  near  the  red  ore.  It  is  a  common  ore  in  the  North  of 
England  and  in  Scotland,  in  Belgium,  Silesia,  Spain,  and 
Sardinia.  It  is  an  impure  carbonate,  having  a  peculiar 
columnar  structure,  a  dirty  red  color,  and  moderate  cohesion. 


OKES  OF  ZINC.  71 

It  often  contains  lead,  iron,  manganese,  and  cadmium  and 
rarer  metals. 

When  raised  from  the  mine,  the  ores  are  carefully  picked 
over,  and  the  gangue  and  lean  ores  removed  as  completely 
as  possible.  They  are  next  broken  to  small  fragments  or 
powder  under  stamps,  and  washed  very  thoroughly. 

They  are  calcined  and  smelted,  the  calcination  rendering 
them  porous  and  more  easily  reducible  by  driving  out  moist- 
ure and  carbonic  acid.  The  process  is  generally  conducted 
in  reverberatory  furnaces,  but  sometimes  in  kilns. 

In  smelting,  the  ore  is  mixed  with  half  its  weight  of  any 
cheap  form  of  carbon,  the  two  materials  being  well  ground 
and  mixed,  and  is  reduced  at  a  high  temperature  in  retorts 
or  muffles,  usually  three  feet  long  and  eighteen  inches  high, 
a  half-dozen  being  heated  in  a  single  furnace.  The  reduced 
metal  passes  off  in  the  state  of  vapor,  condenses  as  it  issues 
through  a  properly  formed  channel,  and  flows  into  the  moulds 
placed  to  receive,  it.  The  process  is  therefore  one  of  distilla- 
tion. 

Two  processes  are  in  use — the  Belgian  and  the  Silesian. 
In  the  former  the  distillation  is  carried  on  in  cylindrical 
retorts,  four  or  five  diameters  in  length,  put  up  in  "  benches," 
which  consist  of  forty  or  fifty,  or  even  more,  set  in  several 
rows,  one  above  another,  within  a  furnace  stack,  with  one 
end  depressed  and  accessible  from  the  front.  Two  or  four 
furnaces  are  often  built  in  one  structure,  and  their  products 
of  combustion  are  led  to  a  single  chimney.  The  upper  rows 
of  retorts  are  charged  with  about  sixteen  pounds  (7.26  kilo- 
grammes), and  the  lower  with  fifty  per  cent,  more  ore,  the 
charge  being  first  moistened  to  prevent  the  formation  of  dust. 
The  furnaces  and  retorts  are  heated  separately,  and  after 
three  or  four  days'  heating  the  former,  the  latter  are  intro- 
duced. The  open  end  of  the  retort  is  closed  by  a  fire-clay 
plug  to  which  an  iron  funnel-shaped  cap  is  fitted  to  conduct 
the  distilled  zinc  away,  while  acting  also  as  a  condenser. 
Every  two  hours  these  are  removed  and  cleared  out,  the  zinc 
collected  in  them  thrown  into  a  ladle,  and  the  unreduced 
oxide  found  with  it  is  re-worked  later.  The  retorts  are  re- 


72   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

charged  every  twelve  hours,  and  the  furnaces  are  only  stopped 
for  repairs  about  once  in  every  two  months.  The  zinc  is 
poured  from  the  ladle,  when  filled,  into  ingot  moulds. 

In  the  Silesian  process,  the  distillation  is  carried  on  in 
ovens  or  muffles,  which  are  better  calculated  to  bear  high 
temperatures,  and  in  which,  therefore,  the  work  can  be  more 
perfectly  done. 

The  distilled  zinc  runs  down  an  iron  tube,  which  is  the 
condenser,  into  a  small  reservoir  at  the  mouth  of  the  oven. 
Thirty-two  are  set  in- a  furnace.  They  are  re-charged  once  a 
day.  Re-melting  is  carried  on  in  clay-lined  iron  crucibles  or 
kettles.  The  fuel  consumed  in  these  processes  is  from  about 
six  times  the  weight  of  ore  in  the  best  examples  of  Belgian 
work,  to  twelve  or  fifteen  in  the  Silesian  furnaces. 

Zinc  ores  are  often  found  to  contain  lead,  and  their  treat- 
ment by  usual  processes  is  somewhat  difficult.  Thus  Chen- 
hall  *  gives  : 


COMPOSITION   OF   ZINC   ORES. 


CONSTANTINE. 

CAVALO. 

BLUESTONE. 

AMERICAN. 

:Zinc  

IO.64. 

IT    4.O 

2Q    28 

27   2O 

Lead  

4.8l 

17.  14 

I2.QO 

12   OO 

Copper  . 

1  .  3^ 

O   44. 

O    6^ 

O   2O 

Silver  and  Gold    .  . 

o  04. 

o  06 

O   O^ 

Sulphur  

26.85 

je  .  -27 

22.  14 

Iron  .      ... 

IQ    Q^ 

4.   08 

7  16 

Alumina  

2.  -l-l 

I    O2 

Magnesia  

O.22 

Barium  sulphate  
Silica  

26.4.8 

35-04 
1  1  .  IQ 

26.84 

Arsenic. 

o  65 

OTT 

O    I  ^ 

Lime 

o  60 

0.84 

Sulphuric  Acid  

•7  .  C.T. 

Antimony 

o  02 

Oxygen  and  loss  

2-77 

I.  01 

I.  01 

IOO.OO 

IOO.OO 

IOO.OO 



These  ores  are  treated  by  the  Parnell  process  of  dissolving 
in  sulphuric  acid,  and  decomposing  the  sulphate  by  heating 


Proc.  British  Institute  Civil  Engineers  ;  1882-3  I  Part  iv. 


METALLIC  ZINC.  73 

it  with  the  sulphide.  The  loss  is  reported  to  be,  for  lead 
ores,  which  are  similarly  treated,  three  per  cent. 

Commercial  zinc  thus  prepared  usually  contains  some 
lead,  and  may  contain  a  considerable  amount.  Where  needed 
pure,  it  should  be  very  carefully  selected  by  analysis. 

42.  Metallic  Zinc  is  a  bluish  white  metal  known  to  the 
trade  as  "  spelter" 

Its  atomic  weight  is  65.  It  is  rather  brittle,  and  can  be 
rolled  satisfactorily  only  when  heated  somewhat  above  the 
boiling  point  of  water.  When  pure,  it  can  be  worked,  with 
care,  into  bars  or  sheets  at  ordinary  temperatures.  After 
passing  the  boiling-point,  it  again  gradually  loses  its  ductility 
and  malleability,  and  can  be  powdered  readily  at  a  tempera- 
ture somewhat  below  the  red  heat. 

The  rolling  of  this  metal  was  at  first  accomplished  with 
very  great  difficulty,  from  the  fact  that  its  malleability  is 
confined  to  very  narrow  limits  of  temperature.  For  this 
reason  it  is  always  an  operation  only  entrusted  to  experienced 
hands.  The  most  suitable  temperature  is  about  120°  Cent. 
(248°  Fahr.),  and  this  must  be  maintained  throughout  the 
process.  Below  this  point  the  metal  opposes  too  great  a 
resistance,  and  must  be  re-heated;  above  this  point  it  be- 
comes brittle  ;  at  200°  Cent.  (390  Fahr.),  it  can  be  brayed  in 
a  mortar. 

Zinc  should  be  re-melted  before  being  rolled  into  sheets. 
The  heat  of  fusion  varies  between  400°  Cent,  and  50x3°  Cent. 
(750°  Fahr.  and  930°  Fahr.).  Re-melting  is  generally  per- 
formed in  a  reverberatory  furnace  to  cleanse  the  zinc  of  im- 
purities. The  thickness  of  the  ingots  must  vary  with  the 
final  dimensions  required  ;  this  renders  re-melting  indispens- 
able. 

The  re-melted  plates  are  first  roughed  down  or  rolled 
between  heavy  rolls,  and  after  being  cut  down  to  a  fixed 
weight,  are  taken  to  the  finishing  train,  where  the  rolling  is 
completed.  There  are  thus  two  distinct  operations — the 
roughing  down  and  the  finishing.  Between  the  two,  the 
sheets  are  re-heated  in  annealing  boxes  placed  upon  the 
melting  furnace.  Each  operation  gives  rise  to  a  production 


74  MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS. 

of  scrap,  which  is  more  or  less  large  in  amount  according  to 
the  quality  of  the  metal  and  thickness  of  the  sheet.  This 
scrap,  and  all  defective  sheets,  are  re-melted  with  the  ingots 
from  the  foundry. 

The  fact  that  zinc,  heated  to  a  temperature  exceeding  the 
boiling  point  of  water,  becomes  malleable,  was  discovered 
about  the  year  1805,  and  rolled  sheet  zinc  then  soon  made 
its  appearance  in  the  market,  and  was  used  to  some  extent 
as  a  roofing  material. 

Zinc  is  used  extensively  in  the  form  of  sheets  for  roofing, 
sheathing  of  iron  ships,  domestic  utensils,  etc.,  etc.  Very 
large  quantities  are  used  by  the  engineer  in  the  brass  alloys 
and  in  the  surface-protection  of  sheet-iron.  It  unites  readily 
with  the  other  useful  metals  to  form  alloys,  which  are  usually 
characteristically  different  from  their  constituents.  The  prin- 
cipal of  these  alloys  are  the  brasses,  or  alloys  with  copper. 
The  metal  is  also  often  mixed  in  small  proportions  with  the 
bronzes,  or  copper-tin  alloys,  to  form  the  copper-tin-zinc  ter- 
nary alloys  often  used  in  machine  construction.  Of  the 
world's  product  of  this  metal,  amounting  to  above  200,000 
tons,  the  United  States  produces  twenty  per  cent.  Belgium 
and  Germany  make  two-thirds. 

Zinc  sheets  of  standard  dimensions  have  the  following 
weights  : 


THICKNESS   AND   WEIGHT  PER   SQUARE   FOOT. 


Inch. 
.0311  =  10  oz. 

.0457  =   12  OZ. 


Inch. 

.0534=  I40Z. 
.0611  =  16  oz. 


Inch. 

.0686  =  18  oz. 
.0761  =  20  oz. 


Cast  zinc,  as  well  as  rolled,  is  often  used  in  the  manufac- 
ture of  ornamental  work ;  it  takes  the  impression  of  the 
mould  as  sharply  as  good  foundry  iron,  and  is  especially  liked 
for  small  work. 

A  prize  offered  in  1826  by  the  Society  for  Advancement 
of  Industry  in  Prussia,  led  to  the  discovery,  by  Krieger,  of 
Berlin,  that  hollow  ware  can  be  cast  in  zinc,  and,  by  Geiss, 
that  it  would  make  good  architectural  ornaments.  An  exten* 


METALLIC  ZIXC. 

sive  consumption  of  the  metal  for  these  purposes  at  once 
arose,  and  the  applications  of  zinc  in  these  directions  are 
becoming  rapidly  more  general.  It  is  largely  used  in  decora- 
tion, as  a  substitute  for  bronze,  and  to  a  considerable  extent 
in  the  construction  of  large  statuary ;  in  this  case,  however, 
the  mass  is  usually  built  up  of  smaller  parts  soldered  together. 
Berlin  has  been  the  head-quarters  of  this  industry. 

Zinc  castings  made  at  a  high  temperature  are  brittle  and 
crystalline ;  when  cast  at  near  the  melting  point,  they  are 
comparatively  malleable.  It  is  hardened  by  working,  and 
must  be  occasionally  annealed. 

The  value  for  sheathing  and  for  work  exposed  to  the 
weather,  arises  from  the  permanence  and  impenetrability  of 
the  coating  which  forms  over  its  surface — a  basic  carbonate. 

Zinc  is  the  most  strongly  electro-positive  of  the  metals  of 
commerce,  and  is  almost  exclusively  used  as  the  perishable 
element  in  voltaic  batteries. 

It  has  a  specific  gravity  of  6.9  to  7.2,  melts  at  770°  F. 
(410°  Cent.),  and  boils  at  1900°  F.  (1040°  Cent.) ;  its  vapor 
burns  readily  with  a  bluish-white  flame,  forming  the  white 
oxide. 

The  salts  and  the  higher  oxide  of  zinc  are  extensively 
used  in  the  arts,  especially  in  making  paints  and  dyes.  The 
chloride  is  used  in  large  quantities  as  a  preservative  of  timber 
and  as  a  disinfectant. 

Rolled  zinc  is  made  very  much  as  sheet  lead  or  sheet 
copper  is  made ;  but  its  temperature  must  be  kept  at  a  little 
above  the  boiling  point  of  water,  to  secure  the  necessary 
malleability,  and  it  must  also  be  free  from  alloy.  It  is  freed 
from  its  most  usual  constituent,  lead,  by  re-melting  the  spel- 
ter, as  received  from  the  furnace,  on  the  hearth  of  a  rever- 
beratory  furnace  which  has  a  gradual  slope  terminated  by  a 
basin,  into  which  the  melted  metal  flows,  and  in  which  the 
zinc  and  lead  separate,  the  lead  settling  to  the  bottom,  while 
the  zinc  lies  on  the  top.  The  zinc  is  ladled  out  and  cast  into 
ingots  for  the  mill. 

These  ingots  are  warmed  to  the  proper  temperature,  and 
then  rolled  into  sheets,  and  sometimes  into  bars,  between 


76  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

rolls  kept  heated  by  the  passage  through  them  of  steam  of 
moderate  pressure. 

Galvanized  iron  is  sheet  iron  covered  with  a  coating  of 
zinc  by  immersion  in  molten  zinc. 

Zinc  is  produced  in  the  United  States  to  the  amount, 
annually,  of  about  60,000  tons  (1888),  and  the  production  is 
rapidly  increasing.  At  least  one-half  comes  from  Illinois, 
one-third  from  Missouri,  and  nearly  as  much  from  Kansas. 
New  Jersey  supplies  zinc  of  excellent  quality,  and  furnishes 
all  that  is  exported,  sending  abroad  over  40,000  tons  of  ore. 
The  gas-furnace  of  Siemens  is  now  adapted  to  smelting  zinc, 
and  is  coming  into  general  use  in  consequence  of  its  cheap- 
ness of  operation  and  manageability.  The  known  deposits 
of  zinc  are  being  rapidly  worked  out. 

The  importations  of  foreign  zinc  into  the  United  States 
are  more  than  equalled  by  the  export  of  special  grades  of 
American  zinc  to  Europe,  where  the  metal  is  much  sought 
on  account  of  its  high  value  for  the  manufacture  of  military 
rifle  cartridge  cases. 

The  amount  of  coal  used  for  one  pound  of  zinc  is  the  fol- 
lowing at  the  different  works,  the  Eastern  works  using  anthra- 
cite principally,  and  the  Western  works  using  bituminous  coal : 


FUEL. 

REDUCTION. 

TOTAL. 

Passaic      .        ..      . 

4.  «? 

I  3 

5  8 

Bergen  Point  

e  .  c 

I    Q 

7.4. 

Lehigrh 

4c 

I    7 

6    2 

Carondelet  

4.4 

I    2 

5  6 

The  yield  of  zinc  is  stated  to  be 

Lehigh,  for  calamine 73 . 5  per  cent. 

Lehigh,  for  blende 70 .  o       " 

Passaic,  for  calamine 80 .  o       " 

Martindale,  for  blende  and  silicates 73 -O       " 

Carondelet,  for  silicates 76. So     " 

Of  the  whole  quantity  consumed  in  the  United  States  in 
1883,  about  ten  per  cent,  is  used  in  galvanizing  wire. 


LEAD.  77 

43.  Lead  (Plumbum  ;  Pb.)  is  a  bluish-white,  lustrous,  in- 
elastic metal,  so  soft  that  it  may  be  easily  scratched  with  the 
finger-nail.  It  has  too  little  tenacity  to  be  readily  drawn 
into  fine  wire,  although  some  lead  wire  is  found  in  the  market. 
It  is  very  malleable,  and  is  very  extensively  used  in  the  forms 
of  sheet-lead  and  lead-pipe.  It  is  very  heavy  (S.  G.  11.4), 
and  is  easily  fusible,  melting  at  620°  F.  (327°  C.) ;  it  absorbs, 
in  fusing,  5.4  metric  thermal  units  per  kilogramme  (9.8  B.  T. 
U.).  Its  specific  heat  is  0.03  at  low  temperature,  and  0.04 
near  the  melting  point.  The  coefficient  of  expansion  is  given 
by  Calvert  and  Johnson  at  0.00003.  It  is  a  very  bad  conduc- 
tor of  both  heat  and  electricity.  At  high  temperatures  it 
becomes  slightly  volatile ;  in  this  respect  and  in  changing  in 
character  from  ductile  to  brittle  as  the  melting  point  is 
approached,  it  resembles  zinc  somewhat. 

Oxidation  occurs  but  slowly  in  dry  air,  and  the  oxide 
forms  a  protecting  coating  over  the  metal.  When  exposed 
to  moist  air  containing  carbonic  or  acetic  acid,  however, 
oxidation  progresses  rapidly.  Lead  is  readily  dissolved  in 
water  containing  carbonic  acid  or  salts  of  nitric  acid ;  the 
solution  is  poisonous,  as  all  the  salts  of  lead  are  cumulatively 
poisonous. 

Lead  oxides  are  of  great  value  in  the  arts.  "  Red  lead," 
or  minium  (Pb4O5),  is  used,  mixed  with  drying  oils,  as  a  pig- 
ment, and  by  the  engineer  as  a  cement,  in  the  latter  case 
often  mixed  with  "  white  lead,"  a  basic  carbonate  [2PbCO3Pb 
(OH)2],  which  admixture  gives  greater  hardening  and  cement- 
ing power;  this  quality  is  often  still  further  improved  by  the 
addition  to  the  cement  of  red  and  white  lead,  in  oil,  in  equal 
parts,  of  several  times  its  weight  of  borings  of  iron  with  a 
little  sal-ammoniac  and  sulphur.  Red  lead  is  much  used  in 
the  manufacture  of  flint  glass. 

Lead  compounds  are  easily  identified  by  the  formation  of 
the  yellow  oxide  in  the  reducing  flame  of  the  blow-pipe. 
Lead  salts  in  solution  give  a  black  precipitate  when  exposed 
to  the  action  of  sulphuretted  hydrogen. 

Lead  was  known,  but  was  of  little  importance  in  the 
earliest  historic  times.  It  is  supposed  to  have  been  discov- 


78   MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS. 

ered  later  than  either  copper  or  tin.  It  was  the  custom, 
apparently,  among  the  Hebrews  and  their  contemporaries,  to 
engrave  records  of  importance,  and  which  were  desired  to  be 
made  permanent,  upon  tablets  of  lead  with  an  iron  stylus. 
The  Phoenicians  used  the  metal  in  weighting  anchors,  and 
sold  it  to  the  Greeks  and  the  Egyptians.  It  was  used  by  the 
Babylonians,  according  to  Herodotus,  in  securing  iron  cramps 
in  masonry,  probably  in  the  same  manner  as  is  usual  in 
modern  engineering. 

44.  The  Ores  of  Lead  are  galena  or  the  sulphide,  and 
the  carbonate.  Nearly  all  the  lead  of  commerce  is  obtained 
from  galena,  which  consists  of  eighty-seven  per  cent,  lead, 
nearly,  when  pure,  and  13  per  cent,  sulphur;  it  nearly  always 
contains  silver,  sometimes  in  quite  large  amounts,  varying 
from  a  fraction  of  one  per  cent,  up  to  fifty  per  cent. ;  arsenic, 
copper,  iron,  and  zinc.  The  ore  is  very  often  worked  for  its 
silver.  Galena  is  worked  in  Saxony  and  Bohemia,  in  Eng- 
land, Spain,  and  the  United  States  ;  it  is  usually  found  in 
the  palaeozoic  rocks.  The  ores  worked  in  the  United  States 
generally  contain  comparatively  little  silver,  and  are  quite 
pure.  They  are  found  principally  in  the  valley  of  the  Mis- 
sissippi. Enormous  deposits  exist  in  Missouri,  Iowa,  Illinois, 
and  Wisconsin,  in  crevices  and  pockets  in  those  lower  Silu- 
rian rocks  which  have  lately  been  distinctively  known  as  the 
galena  limestone.  These  deposits  have  been  worked  only 
from  about  1820,  although  the  existence  of  the  ores  had  been 
then  known  more  than  a  century.  The  ores  of  lead  occur  all 
through  the  Alleghanian  districts  of  the  eastern  United 
States,  but  none  are  profitably  worked. 

Lead  ores  are  now  often  smelted  in  furnaces  of  the 
Rachette  type,  i.e.,  having  a  rectangular  form  and  widening 
section  from  bottom  to  top.  These  permit  the  use  of  a 
low  pressure  of  blast,  and  comparatively  unlimited  magnitude 
of  charge.  The  fuel  is  usually  charcoal  or  coke,  or  both,  the 
flux  is  iron  and  limestone,  or  sometimes  silica,  and  the  ore  is 
broken  to  the  size  of  the  fist  or  of  an  egg.  The  ore  is  often 
first  roasted.  The  total  fuel  used  amounts  to  from  fifteen  to 
twenty-five  per  cent,  of  weight  of  charge. 


THE   SMELTING   OF  GALENA.  79 

45.  The  Smelting  of  Galena  is  performed  in  a  rever- 
beratory  furnace,  first  roasting  it,  usually  adding  a  little  lime, 
until  it  is  largely  converted  into  lead  sulphate.  An  increase 
of  temperature  of  furnace  with  an  oxidizing  flame  drives  off 
the  sulphur  in  the  form  of  sulphurous  acid,  and  the  reduced 
metal  is  tapped  off.  Some  of  the  lead  is  volatilized,  and  is 
condensed  in  the  flues  or  in  a  vacuum  chamber,  constructed 
for  the  purpose,  in  which  it  meets  with  a  shower  of  water. 

Antimony  and  tin,  when  present  in  objectionable  propor- 
tions, are  oxidized  by  exposing  the  molten  lead,  in  shallow 
pans,  to  the  action  of  the  air.  Silver  is  removed,  often,  by 
the  Pattinson  process  of  concentration,  by  melting,  agitation, 
and  slow  cooling,  with  repeated  separation  of  the  crystalliz- 
ing metal  which  contains  little  silver,  from  the  more  infusible 
portion  which  is  richer  in  the  precious  metal.  The  final 
product  is  subjected  to  the  action  of  the  air  at  high  tempera- 
ture, which  oxidizes  the  lead  and  leaves  the  silver  in  the 
metallic  state. 

The  lead-smelting  process  is  very  largely,  like  the  process 
of  reducing  copper,  one  of  desulphurization.  The  prelimi- 
nary roasting  of  galena  converts  a  part  into  oxide  of  lead,  the 
metalloid  passing  off  in  sulphurous  acid,  while  another  por- 
tion becomes  a  sulphate.  The  whole  mass  is  then  melted, 
the  sulphur  all  passing  off  in  sulphurous  acid,  and  the  metallic 
lead  is  left  behind.  This  is  done  on  the  basin-shaped  hearth 
of  a  reverberatory  furnace,  which  is  about  six  feet  (1.8  metres) 
wide  and  8  feet  (2.44  metres)  long,  and  is  lined  with  slags 
melted  down  in  place.  The  tap-hole  for  the  slag  is  above 
that  for  metal.  The  process  of  smelting  is  conducted  in  four 
operations  or  "  fires." 

The  lead  tapped  off  at  the  first  melting  of  argentiferous 
ores  is  richest  in  silver.  As  soon  as  it  is  out  of  the  furnace  a 
second  charge  is  thrown  in  and  roasted ;  the  dross  from  the 
preceding  charge  is  added. 

Some  lead  is  reduced  and  is  tapped  off  after  an  hour  or 
more,  and  the  remaining  ore  is,  in  the  course  of  about  two 
hours,  converted  into  oxide  and  sulphate. 

The   temperature  of   the  furnace   has   been,  up  to  this 


80  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

period,  kept  below  the  red  heat,  in  order  that  the  ore  may 
not  melt  down  and  the  desired  change  thus  be  checked.  The 
heat  is  now  increased  to  a  full  red,  and  the  reaction  of  the 
oxide  and  sulphates  present  upon  the  sulphide,  leads  to  the 
reduction  of  the  lead,  which  runs  off  freely.  This  process 
occupies  about  an  hour,  and  the  temperature  of  the  furnace 
has  been  alternately  raised  and  depressed  to  facilitate  the 
separation  of  the  metal ;  a  little  lime  being  added,  also,  to 
flux  the  ore. 

The  temperature  is  now  again  raised  for  another  hour  ; 
more  lime  is  added,  and  further  reduction  occurs.  Finally, 
the  furnace  is  heated  to  its  maximum  temperature,  and  held 
at  this  heat  for  three-quarters  of  an  hour  or  more,  when  the 
lead  is  tapped  off,  the  slags  hardened  with  lime,  and  reduc- 
tion is  complete.  The  whole  process  has  occupied  five  hours 
or  more.  The  fuel  consumed  amounts  to  something  more 
than  one-half  the  weight  of  the  ore  smelted. 

The  slag  is  still  rich  in  lead,  and  is  again  worked  separately. 

The  molten  lead  tapped  off  is  often  refined,  as  is  done  in 
purifying  tin,  by  the  use  of  sticks  of  wood  in  the  basin.  It 
contains  a  considerable  amount,  often,  of  silver,  copper,  anti- 
mony, and  iron,  amounting  sometimes  to  several  per  cent. 
This  is  partly  removed  by  the  process  of  "  softening,"  which 
consists  in  running  it  into  a  reverberatory  furnace,  having  for 
its  hearth  a  shallow  basin,  and  there  oxidizing  out  the  im- 
purities by  exposing  it  to  the  oxygen-laden  gases  passing 
over  it.  The  process  of  smelting  has  of  late  been  modified, 
and  is  now  very  generally  conducted  in  blast-furnaces,  instead 
of  in  reverberatory  furnaces. 

When  rich  in  silver,  Pattinson's  process  is  adopted.  This 
consists  in  melting  in  a  series  of  basins,  in  which  the  metals 
gradually  separate.  Lead  crystallizes  at  a  lower  temperature 
than  the  alloy,  and  the  molten  metal  being  allowed  to  cool 
slowly,  crystals  of  comparatively  pure  lead  are  formed,  which 
are  separated  from  the  remaining  mass  which  is  richer  in 
silver,  and  are  transferred  from  one  melting  pot  in  a  series  to 
another;  the  lead  richer  in  silver  being  gradually  separated 
until  that  to  be  sent  to  market  contains  little  to  pay  for 


COMMERCIAL  LEAD.  8 1 

further  working.  The  melting  pots  are  set  side  by  side,  and 
the  purer  lead  is  transferred  from  pot  to  pot  in  one  direction, 
while  that  containing  silver  is  similarly  transferred  in  the 
reverse  direction,  until  the  pots  at  the  extremes  of  the  series 
contain,  the  one  nearly  pure  and  marketable  lead,  while  the 
other  contains  so  much  silver  that  it  can  profitably  be  worked 
to  recover  it.  This  method  is  going  out  of  use. 

46.  Commercial  Lead.— The  lead  is  run  into  "pigs" 
about  3  feet  (0.9  metre)  long,  usually  weighing  about  150 
pounds  (70  kilogs.).  Spanish  "pigs"  weigh  112  pounds  (50 
kilogs.).  A  "  fodder"  is  8  pigs. 

Pig-lead  is  rolled  into  sheets  6^  to  7%  feet  (2  to  2j/(  metres) 
wide,  30  to  35  feet  (9  to  1 1  metres)  long,  and  sent  to  market 
in  rolls.  The  weight  runs  very  nearly  six  pounds  per  square 
foot  for  each  o.i  inch  thickness  (120  kilograms  per  square 
metre  per  centimetre  in  thickness).  Sheet-lead  is  extensively 
used  for  tanks,  sheathing%  etc.,  and  sometimes,  although  less 
than  formerly,  for  roofing.  Lead-pipe  is  made  as  below  by 
forcing  lead  through  an  orifice,  the  size  of  the  pipe  to  be  made, 
over  a  former  which  gives  it  the  required  internal  diameter. 

Lead  shot  is  made  by  dropping  the  molten  metal  from 
the  top  of  a  shot-tower  of  such  height  that  the  globules  of 
the  leaden  rain  thus  produced  may  cool  and  become  solid 
before  striking  the  water  in  a  tank  at  the  bottom,  placed 
there  to  receive  it. 

Lead  pipe  is  now  made  by  a  peculiar  process  called 
"  squirting"  ;  it  was  formerly  made  by  a  process  of  "  draw- 
ing" through  dies.  In  the  modern  process,  the  lead  is 
melted  in  crucible,  or  iron  pots,  and  then  carried  to  a  com- 
pressing chamber  fitted  with  a  plunger  which  is  driven  by 
hydraulic  pressure.  The  lead  is  allowed  to  solidify  and  cool  to 
about  400°  F.  (204°  C.).  The  ram  is  then  forced  down  upon 
it,  and,  at  a  pressure  of  a  ton  and  a  half  or  more  per  square 
inch,  the  lead  flows  freely  from  an  orifice  in  the  bottom  of 
the  chamber,  and  around  an  iron  core  attached  to  the 
plunger,  thus  taking  the  size  desired,  and  issues  in  the  form 
of  a  pipe  of  a  length  determined  by  the  relative  capacity  of 
the  chamber  and  section  of  pipe. 
6 


82   MATERIALS  OF  ENGINEERING—NON-FERROUS  METALS. 

Bar  lead  and  lead  wire  and  rods  are  made  in  the  same 
manner,  but  dispensing  with  the  core  on  the  plunger.  The 
compressing  chamber  is  sometimes  attached  to  the  hydraulic 
press  plunger,  and  rises  against  a  fixed  plunger  in  which  is  the 
orifice  of  issue,  while  the  core  is  fixed  in  the  compressing 
chamber.  This  arrangement  is  more  convenient  and  causes 
less  frictional  resistance.  Tin-lined  pipe  is  often  made. 

The  alloys  of  lead  will  be  referred  to  later.  The  oxides 
and  salts  have  great  value  in  the  arts. 

White  lead,  the  carbonate  of  lead,  is  made  by  exposing 
sheet-lead  to  carbonic  acid  and  moisture.  The  lead  is  coiled 
up  in  pots,  piled  in  heaps  and  covered  with  spent  tan-bark 
and  horse-dung.  A  little  acetic  acid,  in  each  pot,  attacks 
the  metal,  forming  the  acetate,  which  is  then  altered  into 
carbonate  by  the  carbonic  acid  generated  in  the  hot-bed.  It 
it  used  extensively  in  making  paints. 

Red  lead  is  produced  by  heating  the  protoxide  in  the 
presence  of  oxygen  and  thus  converting  it  into  the  peroxide. 

Litharge  is  made  by  similarly  acting  upon  the  metallic 
lead  and  thus  forming  the  protoxide.  It  is  used  as  flux,  as 
a  constituent  of  cement  and  in  the  manufacture  of  red  lead 
and  of  glass. 

The  salts  of  lead  are  much  used  in  medicine  and  to  a  con- 
siderable extent  in  dyeing.  They  are  all  poisonous. 

Lead  is  now  produced  in  the  United  States  at  the  rate 
(1884)  of  about  150,000  tons  annually,  and  the  production  is 
increasing  at  the  rate  of  ten  per  cent,  or  more  a  year.  But 
little  is  imported.  Of  that  produced  in  the  United  States, 
Utah  yields  about  20  per  cent.,  Nevada,  6  to  8  per  cent,, 
Colorado,  over  one-third,  principally  from  Leadville,  and 
Missouri  and  Kansas  15  per  cent. 

Great  Britain  produces  very  nearly  as  much  as  the  United 
States,  reducing  Spanish  and  other  imported  ores,  which  are 
principally  argentiferous.  Spain  exported  nearly  as  much 
more,  and  Germany  quite  as  much. 

47.  Antimony  (Stibium;  ££.),  is  a  grayish  white,  crystal- 
line and  lustrous  metal,  moderately  hard,  extremely  brittle, 
of  inferior  tenacity  and  has  a  peculiar  taste  and  odor.  It 


ANTIMONY ;  BISMUTH.  83 

melts  at  a  low  red  heat,  840°  F.  (450°  C),  and  may  be  dis- 
tilled at  a  white  heat  in  an  atmosphere  free  from  oxygen.  It 
does  not  oxidize  in  dry  air  at  ordinary  temperatures,  but 
takes  up  oxygen  slowly  in  cool,  moist  air,  and  rapidly  when 
hot.  It  expands  while  solidifying,  like  iron.  Its  specific 
gravity  is  6.7. 

The  most  common  ore  is  the  sulphuret,  which  is  found 
abundantly  in  Borneo  and  in  considerable  deposits  in  Eng- 
land, France,  and  Hungary,  and  also  in  California.  It  is 
reduced  by  roasting  to  expel  the  sulphur.  The  salts  of 
antimony  are  poisonous. 

The  metal  is  a  bad  conductor  of  heat  and  electricity,  and 
is  used,  with  bismuth,  is  making  thermo-electric  piles.  Its 
principal  use  is  in  the  manufacture  of  alloys,  as  britannia 
metal,  type  metal,  pewter,  specula,  etc.  It  expands  when 
solidifying  from  fusion.  It  is  rarely  used  alone. 

Antimony  is  found  in  abundance  in  the  Rocky  Mountain 
section  of  North  America,  and  especially  in  California  and 
Nevada.  The  ore  is  usually  a  crude  sulphuret,  containing, 
often,  some  bismuth  and  a  little  silver.  It  is  smelted  at 
several  points  and  sold  in  the  eastern  markets  for  use  in 
making  type  metal,  britannia  ware,  and  babbitt  metal. 

Gray  antimony  was  used  by  the  ancients  for  coloring  the 
hair  and  eyebrows. 

48.  Bismuth  (Bi. ;  atomic  weight,  208)  is  a  brittle,  pink- 
ish white,  heavy,  useful  metal,  having  some  resemblance  to 
antimony.  It  has  a  specific  gravity  of  9.8  to  9.9.  It  expands 
on  solidifying,  at  a  temperature  of  500°  F.  (260°  C.).  Its  co- 
efficient of  expansion  is  0.00134;  specific  heat,  0.0305.  It 
crystallizes  with  remarkable  facility.  It  may  be  distilled  at 
a  high  temperature.  It  is  very  diamagnetic.  Its  principal 
use  is  in  making  alloys. 

The  metal  is  obtained  either  by  reducing  the  sulphide  or, 
oftener,  by  purifying  native  bismuth. 

Its  oxides  and  salts  are  used  in  medicine,  and  in  the  arts 
to  a  moderate  extent,  only,  almost  invariably  alloyed  with 
other  metals. 

Commercial  bismuth  contains  many  impurities,  which  are 


84   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

removed  by  fusion  with  nitre.  Chemically  pure  bismuth  is 
obtained  by  precipitation,  by  dilution  of  its  solution  in  nitric 
acid.  The  bismuth  of  commerce  comes  principally  from 
Germany  and  Bohemia,  and  some  from  Peru.  Deposits  of 
oxides  and  sulphides  have  been  found  in  Utah.*  The 
quantity  mined  is  not  great  and  the  demand  is  small,  not 
more  than  ten  or  fifteen  tons  being  used  in  this  country 
annually.  It  has  about  one-eighth  or  one-tenth  the  value  of 
silver. 

49.  Nickel  (NL;  atomic  weight,  58.8)  is  a  bluish,  nearly 
silver  white  metal,  having  high  lustre,  considerable  ductility 
and  malleability,  and  closely  related,  chemically,  to  iron  and 
cobalt,  which  metals  are  often  associated  with  it,  in  nature. 
It  has  about  the  hardness  of  iron,  but  is  heavier,  having  a 
specific  gravity  of  8.3  to  8.9,  has  about  equal  fusibility,  but  is 
far  less  subject  to  oxidation  and  corrosion.  Its  oxide  is 
white  and  defaces  the  polished  metal  comparatively  little, 
and  is  easily  removed.  Nickel  can  be  either  cast  or  forged; 
but  it  is  generally  used  in  making  alloys  or  in  plating  more 
oxidizable  metals.  It  is  magnetic,  although  much  less  so 
than  iron. 

The  Ores  of  Nickel  are  the  arsenide,  which  is  by  far  the 
most  common,  and  is  known  to  the  miners  as  kupfernickel, 
the  sulphide,  the  sulphate,  and  the  silicate.  Nickel  ores  are 
found  in  France,  Sweden,  Cornwall,  Spain,  Germany,  New 
Caledonia,  and  in  Oregon  and  other  localities  in  the  United 
States,  Pennsylvania  supplying  the  greatest  quantity.  The 
ores  are  reduced  by  fluxing  with  chalk  and  fluor-spar,  if 
arseniated,  or  by  roasting  and  then  reducing  with  charcoal 
and  sulphur  to  the  state  of  sulphide,  and  then  by  double 
decomposition  with  carbonate  of  soda,  obtaining  the  car- 
bonate, which  is  finally  reduced  with  charcoal.  The  metal 
was  discovered  and  the  ore  reduced  as  early  as  1751  by  Cron- 
stadt. 

The  nickel  ores  of  Oregon  have  the  following  composition 
as  given  by  Hood,  as  determined  by  analyses  of  ores  sent  to 
San  Francisco : 

*  Polytechnic  Review,  April,  1876. 


NICKEL. 


A. 

B. 

GARNIERITE. 

NOUMEITE. 

Silica    

48.21 

4.0.  is 

4.7   21 

4.7    QO 

Iron  and  alumina  oxide.  .  .  . 
Nickel  oxide   

1.38 
21.88 

i-33 

2Q    66 

1.66 

24   OI 

3.00 
24  OO 

IQ.QO 

2  1.  7O 

21  66 

12    51 

Water      

6  61 

7.OO 

5oc 

12    71 

A.  Amorphous. — Hardness,    2.5  ;    specific   gravity,    2.45  ; 
color,  pale  apple  green,  becoming  lighter  by  exposure.     Ad- 
heres to  tongue  ;  not  unctuous.     Does  not  fall  to  pieces  in 
water. 

B.  Amorphous. — Hardness,  2.0-2.5  ;  specific  gravity,  2.20 ; 
color,  dark  apple  green,  becoming  lighter  by  exposure.     Ad- 
heres to  tongue ;  unctuous.     Falls  to  pieces  in  water. 

Gamier  it  e.  Amorphous.  —  Hardness,  2.0-2.5  ;  specific 
gravity,  2.27  ;  color,  apple  green.  Adheres  to  tongue ;  not 
unctuous.  Falls  to  pieces  in  water. 

Noumeite.  Amorphous. — Hardness,  2.5  ;  specific  gravity, 
2.58;  color,  dark  apple  green.  Does  not  adhere  to  tongue; 
unctuous.  Does  not  fall  to  pieces  in  water. 


NICKEL   ORE  A. 

This  mineral  is  amorphous,  and  much  broken  up  with 
bands  or  plates  of  white  silica,  which  forms  in  many  cases  a 
complete  network  to  inclose  the  nickel  mineral.  Other  speci- 
mens, however,  of  the  same  ore  are  quite  massive,  with  the 
silica  in  nodules. 

In  color  it  is  a  beautiful  pale  apple  green,  which  darkens 
and  becomes  more  translucent  on  immersion  in  water. 

It  does  not  fall  to  pieces  when  placed  in  water,  but  gives 
off  bubbles  of  air  for  some  minutes. 

A  piece  placed  on  the  tongue  adheres  strongly. 

It  is  not  greasy  to  the  touch. 

Streak — pale  green, 

When  heated  in  a  closed  tube  it  becomes  gray,  and  on 
platinum  wire  with  borax  gives  the  usual  nickel  bead. 


86  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

NICKEL   ORE,    B. 

This  ore  strongly  resembles  garnierite,  except  in  its  color 
being  darker,  and  the  fact  that  it  is  slightly  unctuous  to  the 
touch. 

It  falls  to  pieces  with  a  sharp  crackling  sound  when 
placed  in  water,  splitting  into  conchoidal  fragments,  and, 
like  the  other  ore,  gives  off  air  bubbles,  but  not  to  so  great 
an  extent. 

Heated  in  a  closed  tube  it  gives  off  water,  loses  its  color 
and  becomes  gray. 

Before  the  blowpipe  it  gives  the  usual  nickel  bead. 

It  is  not  so  soluble  in  acids  as  the  other  variety,  but  in 
one  of  the  shafts  of  the  district  was  found  a  decomposed 
variety  of  this  ore,  which  was  quite  soluble  in  acids. 

The  analyses  here  given  are  the  mean  results  of  examina- 
tion of  four  different  samples  of  each  ore  ;  they  show  the 
percentage  of  nickel  protoxide  to  be  from  23.88  in  A  to  29.66 
in  B.  The  average  yield  of  all  that  has  been  mined — taking  a 
fair  sample — is  stated  to  be  11.20,  which  is  a  high  average 
yield. 

These  ores  are  silicates  of  nickel  and  magnesia  from 
Douglas  Co.,  Oregon. 

50.  Uses  of  Nickel. — Nickel  plating  by  the  electric  cur- 
rent was  practised  experimentally  by  Jacobi  and  Becquerel 
in  1862,  but  it  was  commercially  practised  by  Isaac  Adams, 
of  Boston,  some  years  later.  The  plating  fluid  is  a  solution 
of  the  double  chloride  or  the  sulphate  of  nickel  and  ammo- 
nium. The  current  is  usually  obtained  from  the  magneto- 
electric  machine.  This  has  become,  during  late  years,  a 
very  important  industry,  and  nickel  plating  is  adopted  by  all 
manufacturers  of  small  articles  of  metal  subject  to  corrosion 
and  tarnishing. 

The  malleability  of  nickel  allows  of  its  being  chased  as 
are  silver  and  gold,  and  with  the  result  of  greater  lustre, 
while  the  qualities  of  brilliancy,  hardness,  and  durability, 
whether  used  solidly  or  in  electro-plating,  make  it  very 
suitable  for  table  service. 

The   sheet-nickel   of   commerce    is   as   thin   as  o.oi   inch 


USES  OF  KICKEL.  87 

(0.025  cm.),  and  the  wire  is  nearly  as  fine.  It  can  be  welded, 
with  care,  and  can  be  forged  like  iron. 

Nickel  coinage  was  commenced,  about  1850,  by  Switzer- 
land, and  in  the  United  States  in  1857.  This  application, 
and  nickel  plating  by  electrolytic  action,  absorb  enormous 
quantities.  The  working  of  this  metal  has  been  most  exten- 
sively carried  on  in  the  United  States  by  Mr.  J.  Wharton,  at 
Camden,  N.  J.,  from  sulphuretted  ores  mined  at  Lancaster 
Gap,  Penn.  Sheets  have  been  produced  6  feet  (1.8  m.)  long 
and  2  feet  (6.1  m.)  wide. 

Dr.  Fleitmann's  discovery,  that  a  small  dose  of  manganese 
added  to  the  molten  charge,  when  ready  to  pour  into  the 
moulds,  renders  the  nickel  sound,  strong,  malleable,  and 
ductile,  has  greatly  cheapened,  as  well  as  improved,  the  prod- 
uct. Fleitmann  has  welded  together  iron  and  nickel,  and 
steel  and  nickel. 

Nickel  is  principally  used  in  the  arts  in  the  manufacture 
of  hollow  ware  which  is  to  be  plated  with  silver,  as  practised 
by  Gorham,  and  for  vessels  of  nickeled  iron  ;  the  latter  are  less 
liable  to  injury  than  when  the  nickel  is  deposited  by  electrol- 
ysis. Iron  thus  plated  with  nickel  can  be  worked  with  nearly 
the  same  facility  as  either  metal  alone. 

Commercial  nickel  often  contains  iron.  Canadian  (Quebec) 
ores  contained,*  in  the  garnet,  calcite,  50.40;  chromite,  6.87; 
chrome  garnet,  49.73,  and  in  pyroxene,  silicon  and  alumina, 
50.60;  iron  oxide,  8.73;  magnesium  and  calcium  oxides, 
35.90;  water,  5.83.  The  reduced  ore  gave:  iron,  71.84; 
nickel,  22.70.  The  slag  contained  no  nickel. 

Commercial  nickel  contains,  usually,  measurable  amounts 
of  carbon,  silicon,  iron  and  often  cobalt. 

The  nickel  plates  now  largely  used  as  anodes  for  nickel 
plating  are  prepared  by  fusing  commercial  nickel,  generally 
with  addition  of  charcoal,  and  casting  in  suitable  form.  The 
subjoined  analyses  by  Mr.  W.  E.  Gard,f  of  such  plates,  show 
that  silica  may  be  reduced  and  retained  as  silicon,  and  that  a 
considerable  amount  of  carbon  may  be  present : 

*  "  Nickel  Ores  "  ;  W.  E.  Eustis.     Trans.  Am.  Inst.  Min.,  Eng. 
f  Am.  Journal  of  Science  and  Art,    1878. 


88   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


NO 

I. 

NO. 

II. 

NO. 

in. 

a. 

V. 

a. 

b. 

a. 

b. 

.530 

•549 

1.  104 

1.080 

i  .900 

1.830 

.303 

.294 

.130 

.125 

.255 

.268 

.464 

•463 

.108 

.110 

.301 

.318 

Cobalt      

.446 

.438 

trace 

trace 

049 

•  CK7 

.266 

.  340 

.  104 

.006 

[Nickel]        

98  .  208 

08.190 

98.392 

98  .  345 

Q7.44O 

97,488 

Total 

IOO.OOO 

IOO.OOO 

IOO.OOO 

IOO.OOO 

IOO.OOO 

IOO.OOO 

No.  I.  was  American  nickel,  manufactured  and  cast  by 
Jos.  Wharton,  at  Camden,  N.  J.  A  careful  examination  by 
means  of  Marsh's  apparatus  showed  not  the  least  trace  of 
arsenic  or  antimony.  No.  II.  was  a  sample  taken  from  a 
cast  nickel  anode  used  by  a  nickel-plating  establishment  in 
New  Haven,  No.  III.  a  sample  taken  from  the  same  anode 
after  it  had  been  used  in  the  plating  bath  until  upward  of 
half  its  weight  had  been  removed.  Solvent  action  had  ex- 
tended quite  through  the  plate,  leaving  as  usual  a  porous 
flexible  mass  retaining  its  original  form.  A  comparison  of 
Nos.  II.  and  III.  shows  that  under  galvanic  action  the  car- 
bon, silicon,  and  iron  of  the  anode  dissolved  relatively  slower 
than  nickel,  while  the  reverse  happens  with  sulphur. 

51.  Aluminum  ;  or,  Aluminium  (AL;  atomic  weight,  27.5), 
is  a  white  silver-like  metal,  very  malleable  and  ductile,  a  good 
conductor  of  both  heat  and  electricity,  uniting  with  oxygen 
only  with  great  difficulty,  and  therefore  little  liable  to  cor- 
rosion either  by  exposure  to  air  or  to  the  action  of  the 
oxygen  acids.  It  dissolves  freely  in  hydrochloric  acid  and  in 
solutions  of  the  alkalis.  It  is  remarkable  for  its  lightness  ; 
its  specific  gravity  being  2.6  to  2.7.  The  salts  of  this  metal 
are  not  expensive,  and  are  used  in  large  quantities  in  the 
arts ;  the  sulphate,  alum,  is  the  most  useful,  and  finds  its 
most  important  applications  in  dyeing  and  calico  printing. 
The  alloys  of  aluminium  are  very  valuable.  Its  remarkable 
lightness,  combined  with  its  strength,  make  it  useful  as  a 


ALUMINUM;   OR,  ALUMINIUM.  gg 

alloys.  Equal  volumes  have  equal  strength  when  steel  has 
about  80,000  pounds  tenacity.  Specific  heat  (Richards),  0.227. 

This  metal  was  discovered  by  Wohler,  in  the  year  1827,  and 
by  him  obtained  in  considerable  quantity,  twenty  years  later, 
by  reduction  with  sodium.  Deville  obtained  it  in  ingots  on 
a  commercial  scale,  and  the  metal  rapidly  became  familiar  to 
chemists.  Rose,  in  1855,  found  that  it  could  be  obtained 
from  cryolite,  in  which  it  exists  as  a  fluoride,  by  reduction 
with  sodium.  Reduction  with  carbon  or  hydrogen  has  not 
succeeded.  Cowle's  process  of  reducing  compounds  of  alu- 
minium, copper,  and  other  metals  in  the  "  electric  furnace  " 
produces  these  bronzes  and  alloys  at  far  less  expense  than 
earlier  methods,  and  has  introduced  a  great  variety  of  alloys 
into  the  market  at  moderate  prices.  Sulphuretted  hydrogen 
gas,  which  readily  tarnishes  silver,  forming  a  black  film  on. 
the  surface,  has  no  action  on  this  metal. 

Next  to  silica,  the  oxide  of  aluminium  (alumina)  forms,  in 
combination,  the  most  abundant  constituent  of  the  crust  of 
the  earth,  in  the  form  of  hydrated  silicate  of  alumina,  clay. 
Common  alum  is  sulphate  of  alumina  combined  with  another 
sulphate,  as  potash,  soda,  etc.  It  is  much  used  as  a  mordant 
in  dyeing  and  calico  printing,  also  in  tanning. 

Aluminium  is  of  great  value  in  mechanical  dentistry,  as, 
in  addition  to  its  lightness  and  strength,  it  is  not  affected  by 
the  presence  of  sulphur  in  the  food.  Dr.  Fowler  obtained 
patents  for  its  combination  with  vulcanite  as  applied  to 
dentistry  and  other  uses.  It  resists  sulphur  in  the  process 
of  vulcanization  so  perfectly  as  to  make  it  an  efficient  and 
economical  substitute  for  platinum  or  gold. 

The  metal,  aluminium,  is  distinguished  from  other  white 
metals  by  its  peculiar  gray-white  color,  differing  from  both 
zinc  and  tin,  and  especially  its  remarkably  low  density,  pos- 
sessing as  it  does,  but  one-third  the  weight  of  copper,  one- 
fourth  that  of  silver,  and  one-eighth  that  of  gold.  It  has  a 
pleasant  metallic  ring  when  struck,  and  confers  a  beautiful 
tone  when  introduced  into  bell-metal.  Deville  made  a  bell 
of  but  44  pounds  (20  kilogs.)  weight,  which  was,  however, 
one  and  a  half  feet  in  diameter  (^  metre),  and  exhibited  an 


90  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

exquisite  timbre  ;  it  was  presented  to  the  Royal  Society 
in  1868. 

It  is  sufficiently  malleable  and  ductile  to  permit  its  being 
rolled  into  thin  sheets  and  drawn  into  fine  wire.  Its  melting 
point  is  at,  or  near,  1,300°  F.  (700°  C.  nearly),  between  the 
fusing  point  of  silver  and  zinc,  and  it  does  not  evaporate  at 
any  temperature  yet  observed.  The  metal  may  be  worked 
cold,  like  copper  or  soft  brass,  and  may  be  coined  perfectly 
and  easily.  Oxidation  occurs  very  slowly  and  it  retains  a 
polish  as  well  as  silver.  It  has  often  been  proposed  for  use 
in  coin,  for  which  purpose  it  is  well  adapted  by  its  beauty, 
lightness,  sonority,  and  non-oxidizing  quality.  Laboratory 
weights  have  been  made  of  the  metal,  and  have  remained 
standard  for  many  years.  Its  solubility  in  the  solutions  of  the 
Alkalis  is,  as  with  copper  and  silver,  such  as  to  prevent  its  use 
for  some  purposes.  It  is  very  extensively  used  in  making 
fine  articles  of  luxury,  and  is  proposed  for  use  for  philo- 
sophical and  engineering  apparatus,  and  for  utensils  to  be 
used  in  the  household. 

Alloys  of  aluminium  with  other  metals,  with  the  excep- 
tion of  copper,  are  little  known  and  are  not  in  use.  There 
are  several  manufactories  of  the  metal  producing  a  half 
ton,  or  less,  annually.  Its  cost  is  five  per  cent,  of  that  of 
silver  ;  that  of  the  bronze  is  five  per  cent,  of  that  of  the  metal 
and  somewhere  about  that  of  copper-tin  bronze.  See  page  305. 

52.  Mercury  (Hydrargyrum  ;  Hg.),  often  called  quicksilver, 
is  used  by  the  engineer  for  a  number  of  important  purposes. 
It  is  a  dense  fluid  metal,  having  an  atomic  weight,  200,  a 
specific  gravity  of  13.6,  a  specific  heat  of  0.032  to  0.0333  as  it 
passes  from  the  solid  to  the  liquid  state,  a  coefficient  of  ex- 
pansion, according  to  Regnault,  of  from  0.00018  to  0.000197 
as  its  temperature  rises  from  the  freezing  point  of  water, 
0°,  to  350  Cent.  (32°  to  662°  F.)  Its  latent  heat  of  fusion  is 
2.82  metric  units  per  unit  of  weight  (5.08  British).  It  boils 
at  about  350°  C.  (662°  F.),  forming  a  colorless,  transparent, 
poisonous  vapor,  and  evaporates  at  all  temperatures.  The 
density  of  its  vapor,  according  to  Dumas,  is  6.976.  It  unites 
freely,  at  ordinary  temperatures,  with  several  other  metals 


MERCURY.  91 

forming  "  amalgams."  Iron  and  platinum  are  not  among 
these  metals.  Mercury  is  therefore  preserved  in  iron  bottles. 

The  Ores  of  Mercury  are  cinnabar,  "vermilion,"  which 
is  the  sulphide,  and  calomel,  the  chloride ;  the  former  is 
the  usual  source  of  the  mercury  of  commerce.  The  metal 
is  sometimes  found  native,  in  small  quantities ;  it  is  fre- 
quently alloyed  slightly  with  silver.  The  ores  of  mercury 
are  principally  mined  in  California ;  but  large  quantities 
are  produced  also  in  Spain,  Austria,  and  China. 

Mercury,  or  "  Quicksilver,"  is  only  produced  in  the  United 
States,  in  California,  where  it  is  obtained  from  the  red  sul- 
phide (cinnabar).  The  quantity  produced  is  not  far  from 
60,000  flasks  of  76^  pounds  each,  per  annum,  and  one-fourth  as 
much  more  is  imported.  Its  principal  use  is  in  the  manufac- 
ture of  vermilion  (sulphide  of  mercury),  and  amalgamating 
mirrors. 

Cinnabar  is  dark  brown  in  color,  earthy  in  texture,  and 
very  heavy,  its  specific  gravity  being  8.2  ;  abrasion  produces 
a  red  powder  and  a  red  streak  on  the  mass.  The  ore  is 
reduced  by  distillation  and  usually  with  considerable  loss  of 
vapor.  The  ore  is  broken  up  into  pieces  somewhat  larger 
than  an  egg,  and  roasted  in  a  deep  furnace,  of  circular  form, 
closed  at  the  top  and  connected  by  flues  with  a  set  of  con- 
densing chambers  in  which  the  mercury  is  condensed  by 
contact  with  iron  plates,  over  which  cooling  streams  of  water 
are  kept  flowing.  The  charges  weigh  700  or  800  pounds 
(318  to  363  kilogrammes),  and  are  worked  off  in  about  three- 
quarters  of  an  hour;  the  fuel  used  per  charge  is  25  or  30 
pounds  (i  1.3  or  13.6  kilogs.)  of  charcoal.  In  some  cases,  as  in 
India,  a  reverberatory  furnace  is  used  in  reducing  the  cinnabar, 
when  the  ore  is  lean.  In  still  other  cases,  lean  ores  are  dis- 
tilled in  small  iron  retorts,  holding  about  70  Ibs.  (32  kilogs.), 
with  lime,  and  the  vapors  are  condensed  in  stone  bottles  half 
filled  with  water,  or,  the  retorts  are  larger  and  contain  as 
much  ore  as  the  furnace  above  described.  Condensation  is 
effected  in  a  "  hydraulic  main,"  kept  cool  by  immersion  in  a 
trough  of  water. 

Mercury,  as  distilled,  usually  contains  bismuth,  lead,  and 


92   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

zinc,  and  is  often  re-distilled  in  the  iron  bottles  in  which  it  is 
purchased  from  the  smelter,  or  purified  by  washing  with 
dilute  nitric  acid.  A  subsequent  washing  with  water  and 
drying  with  filter-paper  and  then  warming  it,  leaves  it  in 
good  condition.  It  is  also  purified  by  shaking  with  powdered 
sugar  or  with  charcoal,  the  impurities  being  thus  oxidized  out 
by  contact  with  air. 

This  metal  is  used  in  many  kinds  of  philosophical  appa- 
ratus, in  the  pressure  gauges  used  for  standardizing  steam 
gauges,  in  the  barometer,  in  "  silvering "  mirrors,  and  in  a 
few  alloys. 

Mercury  was  the  last  metal  discovered  by  the  ancients, 
and  is  supposed  to  have  been  known  four  or  five  centuries 
before  the  Christian  era.  Red  cinnabar,  its  sulphide,  was, 
however,  used  as  a  cosmetic  several  hundred  years  earlier, 
and  was  imported  into  Greece  and  Italy,  in  enormous  quanti- 
ties, from  the  Spanish  mines  of  Almaden.  The  Peruvians 
made  similar  use  of  it  at  the  time  of  the  discovery  of  their 
country  by  Pizarro. 

53.  Platinum  (Pt.)  is  a  metal  possessing  qualities  of  the 
highest  value  in  the  arts  ;  but  its  considerable  cost  forbids 
its  common  use.  It  is  so  named  from  the  Spanish  platina, 
the  diminutive  of  plata,  silver,  because  of  its  white,  silvery 
color.  It  is  found  in  the  mountainous  portions  of  South 
America,  Central  America,  Mexico  and  California,  in  the 
West  Indies,  and  in  the  Ural  Mountains,  in  the  metallic  state, 
but  mingled  with  ore  of  iron,  copper,  and  the  rarer  metals, 
and  usually  alloyed  with  a  small  quantity  of  indium.  Its 
atomic  weight  is  197.4. 

The  metal  is  purified  by  solution  in  a  mixture  of  nitric 
and  hydrochloric  acids,  precipitation  by  potassium  chloride  of 
the  double  chloride  of  potassium  and  platinum,  re-solution  by 
nitro-hydrochloric  acid  and  reprecipitation  by  sal-ammoniac, 
sometimes,  after  repeated  solution,  as  the  double  chloride  of 
ammonium  and  platinum.  The  volatile  element  is  driven  off 
by  heating,  and  the  "  spongy  platinum  "  remaining  is  welded 
into  a  solid  mass,  after  cleansing  by  trituration  and  washing. 

Commercial  Platinum  always  contains  osmium  and  usually 


PLATINUM.  93 

silicium  and  iridium.  Fusion  in  the  oxy-hydrogen  flame 
with  proper  fluxing  removes  these  metals  by  oxidation  and 
the  promotion  of  slag.  Deville  and  Debray  fuse  the  ore 
with  galena  in  a  small  reverberatory  furnace,  and,  fluxing  with 
glass  and  litharge,  obtain  an  alloy  of  lead  and  platinum  nearly 
free  from  other  metals.  This  is  expected  to  remove  the  lead, 
and  the  platinum  so  obtained  is  refined  on  the  lime-covered 
hearth  and  thus  obtained  in  a  very  pure  state. 

Various  other  ways  are  sometimes  practised.  The  best 
method  of  compacting  the  metal  is  by  fusion,  which  can  be 
accomplished  by  the  oxy-hydrogen  flame  in  a  little  furnace 
made  by  forming  a  cavity  between  blocks  of  lime. 

Platinum  is  nearly  as  ductile  as  gold  and  silver,  and  is 
only  exceeded  in  malleability  by  those  metals  and  copper. 
It  is  white  like  silver  and  has  nearly  as  high  a  lustre.  It  is 
softer  than  silver  and  about  as  hard  as  copper;  but  it  is 
rapidly  hardened  by  the  addition  of  traces  of  iridium  or  of 
rhodium.  Its  specific  heat  is  0.03243  at  common  tempera- 
tures, according  to  Regnault.  The  coefficient  of  expansion 
is  0.0000068  per  degree,  Cent.,  according  to  Calvert  and 
Johnson,  0.0000085  per  Bordaz,  o.oooooi  according  to  other 
authorities,  varying  according  to  purity  and  physical  condi- 
tion. Platinum  can  only  be  fused  by  the  oxy-hydrogen 
flame  or  the  voltaic  arc.  It  is  the  heaviest  of  the  metals 
used  in  the  arts,  having  a  specific  gravity  of  21.15  to  21.5. 
This  metal  is  not  oxidizable  in  the  air  or  by  any  acid,  although 
a  mixture  of  nitric  and  muriatic  acids  will  slowly  dissolve  it. 
At  high  temperatures,  alkalis  will  produce  corrosion  by  con- 
tact with  it,  as  will  potassium  sulphate,  and  sulphur, 
phosphorus  and  arsenic.  Chlorine  attacks  it  slightly,  iodine 
and  bromine  not  at  all. 

Platinum  is  principally  used  in  the  manufacture  of  vessels 
required  to  resist  heat  or  the  action  of  acids,  as  crucibles, 
evaporating  basins,  stills  or  retorts  used  in  the  concentration 
of  sulphuric  acid,  etc.  Carbon  and  silica  corrode  it,  and  the 
metals,  generally,  freely  alloy  with  it ;  its  applications  are 
thus  somewhat  restricted. 

Platinum  was  discovered  by  the  Spaniards,  in  the  sixteenth 


94   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

century,  in  the  gold  mines  worked  at  the  time,  on  the 
Isthmus  of  Darien  ;  it  only  became  valuable  in  the  arts  two 
centuries  later,  after  Sickengen  had,  in  1772,  found  that  it 
could  be  welded  at  a  single  white  heat ;  it  then  came  into 
demand,  its  hardness,  strength,  freedom  from  liability  to 
oxidation,  and  especially  its  infusibility,  giving  it  a  value 
nearly  equal  to  that  of  gold. 

54.  Magnesium,  (Mg.;  atomic  weight,  24)  is  a  silver 
white,  lustrous  metal,  ductile  and  malleable,  very  light  (s.  g., 
1.75),  readily  combustible,  easily  cut  and  worked,  and  resem- 
bling alumina  in  many  respects.  It  melts  and  volatilizes 
like  zinc,  and  at  about  the  same  temperature.  In  the  form  of 
powder  or  thin  wire  or  ribbon,  it  takes  fire  like  a  shaving  of 
wood  and  burns  rapidly,  with  an  intense  bluish  white  light 
very  rich  in  actinic  rays. 

It  abounds  in  dolomitic  limestone  in  the  form  of  silicate 
and  carbonate  of  magnesia,  in  carncllite,  a  double  chloride  of 
magnesium  and  potassium,  from  which  it  is  reduced  by 
sodium,  using  fluor  spar  as  a  flux,  purifying  it  by  distillation. 

Magnesium  has  been  manufactured  by  two  establish- 
ments, the  American  Magnesium  Company,  Boston,  United 
States,  and  the  Magnesium  Metal  Company,  Manchester, 
Great  Britain.  The  English  manufactory  produced  by  far 
the  most.  The  former  furnished  large  quantities  for  the 
English  army  during  the  campaign  in  Abyssinia,  the  metal 
being  employed  extensively  for  signals. 

Magnesium  can  readily  be  ignited  at  the  flame  of  a  candle. 
Combustion  is  frequently  interrupted  by  the  dropping  off  of 
the  burning  portion,  so  that  it  becomes  necessary  to  feed  the 
unburnt  portion  into  the  flame  continually.  The  wire  burns 
to  the  best  advantage  if  inclined  at  an  angle  of  about  450. 

An  uninterrupted  and  very  brilliant  combustion  is  produced 
by  lamps  especially  constructed  for  this  purpose.  Such  a 
lamp*  is  made  by  the  American  Magnesium  Company.  The 
strips  of  magnesium  are  rolled  up  on  cylinders  in  the  upper 
part  of  the  apparatus.  These  strips  are  unrolled  by  clockwork 

*  From  designs  patented  by  R.  H.  Thurston,  1865.  New  Marine  Signal 
Light :  Journal  Franklin  Institute,  1866. 


ARSENIC.  95 

in  the  lower  part  of  the  apparatus,  and  are  carried  between 
two  small  rollers,  the  uniform  motion  of  which  feeds  them 
regularly  into  the  lamp,  where  they  are  ignited.  The  ashes 
are  cut  off  at  intervals  by  means  of  eccentric  cutters,  and 
collect  in  the  bottom  of  the  apparatus.  A  small  chimney  is 
added,  which  is  very  important,  as  producing  a  draught  of 
air  directly  through  the  flame.  A  portion  of  the  products  of 
combustion  is  thus  carried  away,  and  the  flame  becomes  very 
intense,  while  it  is  less  so  without  a  draught.  This  lamp  has 
been  found  very  efficient,  especially  for  marine  signals.  At 
trials  made  at  sea,  on  two  vessels  stationed  eight  miles  apart, 
the  signals  could  be  readily  distinguished ;  it  is  said  to  be 
visible  28  miles. 

Larkin  has  constructed  and  patented  a  lamp  in  which  the 
magnesium  is  not  employed  as  wire,  or  in  strips,  but  as  a 
powder.  By  this  means  the  clock-work,  or  other  mechanical 
device,  has  been  dispensed  with.  The  metallic  powder  is 
contained  in  a  reservoir,  which  has  a  small  opening  in  the 
bottom.  The  magnesium  powder  flows  through  this  like  the 
sand  in  the  sand-clock.  It  is  intimately  mixed  with  a  certain 
quantity  of  fine  sand,  in  a  manner  diluted ;  first,  in  order  to 
be  able  to  make  the  opening  sufficiently  large ;  furthermore, 
to  produce  a  continuous  flow  of  the  material.  The  mixture 
falls  into  a  metallic  tube,  through  which  illuminating  gas  is 
led  from  the  upper  end.  The  mixture  is  ignited  at  the  lower 
end.  The  flame  is  very  brilliant,  and  the  remaining  sand  falls 
into  a  vessel  placed  below,  while  the  smoke  passes  away 
through  a  chimney.  A  lamp  of  this  character  was  adopted 
in  several  forms  of  signal  apparatus  devised  for  the  Army 
and  the  Navy  Signal  Corps,  by  the  Author,  in  the  years 
1866-70. 

55.  Arsenic  (As.;  atomic  weight,  75)  is  found  native,  but  is 
usually  obtained  from  the  sulphite  or  from  the  alloy  with  iron 
known  as  arsenical  iron.  It  is  also  found  alloyed  with  other 
metals.  It  is  reduced  from  arsenical  pyrites,  or  from  arsenical 
iron,  by  roasting  in  retorts,  the  arsenic  passing  off  by  subli- 
mation and  condensing  outside  as  in  the  zinc  manufacture. 
The  arsenic  of  commerce  is  made  principally  from  German 


96    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

and  Spanish  ores.  The  oxide  is  easily  reduced  by  heating 
with  carbon. 

This  metal  is  a  gray,  lustrous  solid,  of  steely  fracture  and 
color,  having  a  density  of  5.6  to  5.95,  crystallizing  in 
rhombohedra,  volatilizing  at  a  red  heat,  with  a  garlic-like  odor, 
and  oxidizing  easily  at  a  high  temperature,  but  not  readily  at 
a  low  temperature.  It  has  no  value  in  the  arts  of  construc- 
tion and  engineering  except  in  alloys. 

56.  Iridium  (Jr.;  atomic  weight,  197)  is  the  heaviest  of 
useful  metals.  It  was  discovered  in  the  year  1803  by  Tennant, 
who  analyzed  the  metallic  residue  which  remains  when 
platinum  ores  are  dissolved.  Tennant  proved  that  the  platinum 
residues  contained  two  new  metals,  to  one  of  which  he  gave  the 
name  of  indium,  on  account  of  the  varying  color  of  its  salts, 
and  to  the  other  the  name  osmium,  because  of  the  peculiar 
odor  which  its  volatile  oxide  possesses.  Iridium  is  found  in 
the  platinum  ores  in  considerable  quantity  in  the  form  of  the 
alloys  of  platiniridium  and  osmiridium.  The  first  of  these 
occurs  in  grains  and  small  cubes  with  rounded  edges  ;  the 
second,  usually,  in  flat,  irregular  grains,  and  sometimes  in 
hexagonal  prisms.  Iridium,  in  the  cold  state,  resists  the 
action  of  acids  and  alkalies.  It  parts  with  its  oxygen  at  a 
high  heat,  and,  although  it  possesses  a  number  of  valuable 
qualities,  has  been  used,  until  recently,  only  for  the  points  of 
gold  pens.  Its  limited  use  was  caused  by  the  difficulty  of 
obtaining  it  in  metallic  form.  It  is  found  in  Russia,  Brazil, 
California  and  several  other  countries,  and  is  usually  accom- 
panied by  gold  or  platinum.  Since  its  discovery,  numerous 
chemists  and  metallurgists  have  unsuccessfully  endeavored  to 
reduce  the  ore  and  obtain  iridium  in  the  metallic  form. 
Chemists  have  succeeded  in  producing  some  small  pieces  of 
iridium  the  size  of  a  pea  by  means  of  the  oxyhydrogen  blow- 
pipe flame,  the  metal  obtained,  however,  being  porous  and 
valueless.  In  1855,  George  W.  Sheppard,  of  Cincinnati,  suc- 
ceeded in  producing  a  similar  result  with  the  aid  of  a  power- 
ful galvanic  battery.  Later,  John  Holland,  of  that  city, 
began  experimenting  in  the  same  direction,  and  after  several 
years  of  trial  succeeded  in  reducing  the  iridium  ore  to  a  solid 


MANGANESE.  97 

metal  in  common  furnaces.  He  used  phosphorus  as  a  flux, 
by  means  of  which,  it  was  said,  the  metal  could  be  made  to 
fuse  as  easily  as  cast  iron. 

This  new  method  of  fusing  iridosmine  was  discovered  in 
1881  ;  it  consists  in  heating  the  ore  to  whiteness  and  adding 
phosphorus.  The  mass  becomes  at  once  fused,  and  the  phos- 
phide thus  obtained  is  reduced  by  heating  with  lime.  The 
metal  is  exceedingly  hard,  has  a  brilliant  metallic  lustre  and 
is  not  attacked  by  acids;  when  pure,  its  density  is  18.7.* 

The  ore  used  as  above,  and  the  metal,  have  been  examined 
by  Clarke  and  Joslin.f  The  ore  has  a  specific  gravity  of 
19.182,  the  metal  13.77.  The  composition  of  the  latter  was 

Indium 80.82 

Osmium 6.95 

Phosphorus 7.09 

Ruthenium,    Rhodium 7. 20 


102.06 

showing  the  fused  metal  to  be  a  phosphide,  of  the  formula, 
Ir,P. 

Phosphorus  was  found  to  re-act  similarly  with  platinum. 

57.  Manganese  (Mn. ;  atomic  weight,  55)  is  usually 
found  as  a  peroxide,  although  occurring  in  many  other  com- 
pounds. Its  oxide  is  reduced  by  carbon  at  a  white  heat, 
usually  by  heating  the  peroxide  in  powder  with  oil.  The 
metal  is  also  obtained  by  heating  the  chloride  or  fluoride  with 
sodium.  It  is  gray  in  color,  resembling  light  gray  cast  iron, 
usually  weak  and  brittle,  heavy  (s.  g.,  7  to  8)  and  slightly 
magnetic. 

It  has  a  strong  affinity  for  oxygen,  and  it  is  this  which 
makes  it  valuable  in  the  arts.  In  one  of  its  forms  it  is  quite 
different,  however.  As  reduced  from  the  chloride  by  sodium 
it  is  hard  and  does  not  easily  oxidize. 

Manganese  is  always  used  as  an  alloy.  Its  most  usual 
form  is  seen  in  " spiegeleisen"  an  alloy  with  iron  used  in  the 

*  Proc.  Ohio  Mechanics'  Institute,  1882. 
f  Am.  Chemical  Journal,  vol.  v.  No.  4,  1883. 


Qo   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Bessemer  and  other  processes  of  steel-making,  which  is  made 
by  direct  reduction  from  manganiferous  ores  by  the  ordinary 
small  charcoal  blast-furnace.  It  is  cast  either  into  pigs  or 
into  flat  plates.  When  very  rich  in  manganese  and  ccmpari- 
tively  low  in  carbon,  it  is  called  " ferro  manganese."  Spie- 
geleisen  contains  from  3  or  4  to  8  or  10  per  cent,  manganese, 
while  ferro-manganese  contains  10  to  30  per  cent. 

58.  The  Rare  Metals  are  of  no  value  to  the  engineer  in 
his  everyday  work ;  they  are  enormously  costly,  and  possess, 
as  a  rule,  none  of  the  qualities  which  are  essential  to  their 
use  in  construction.  They  are  here  only  referred  to,  to  com- 
plete the  list. 

Gold  and  silver  are  too  well  known  to  demand  description. 
They  are  both  dense,  but  soft,  metals,  difficult  of  oxidation, 
little  subject  to  corrosion,  and  therefore  sometimes  very  use- 
ful in  plating  other  metals  not  readily  attacked  by  acids, 
alloying  with  copper  and  some  other  metals  readily,  and 
forming  compounds  which,  like  these  metals  themselves,  are 
of  little  or  no  value  to  the  engineer. 

Cadmium  is  a  white,  malleable  and  ductile  metal  resem- 
bling tin.  Its  sulphide,  known  as  cadmium  yellow,  is  bright  in 
color  and  has  qualities  of  great  value  to  artists.  The  metal 
is  of  little  use. 

Calcium  is  yellow,  ductile  and  malleable,  and  softer  than 
gold.  At  a  red  heat  it  burns  with  a  dazzling  white  light. 

Erbium  is  very  rare ;  it  resembles  aluminium  in  its  proper- 
ties and  compounds. 

Glucinum  is  white,  malleable  and  moderately  fusible,  re- 
sembling aluminium. 

Lithium  is  a  metal  resembling  silver  in  color.  It  admits 
of  being  drawn  into  wire,  but  has  little  tenacity.  It  is 
remarkable  for  its  lightness  and  the  readiness  with  which  it 
combines  with  oxygen. 

Molybdenum  is  a  silvery  white,  brittle  and  infusible  metal. 
It  never  occurs  native,  and  neither  it  nor  its  compounds  are 
of  practical  use. 

Osmium  is  remarkable  for  its  high  specific  gravity  and 
infusibility. 


COMMERCIAL  METALS.  99 

Palladium  resembles  platinum.  An  alloy  of  20  per  cent, 
with  80  per  cent,  gold  is  perfectly  white,  very  hard  and  doe? 
not  tarnish  by  exposure. 

Rhodium  is  white,  very  hard  and  infusible.  Its  specific 
gravity  is  about  n. 

Ruthenium  resembles  indium.  It  is  rare  and  of  little 
value. 

Strontium  is  yellowish,  ductile  and  malleable ;  it  burns  in 
the  air  with  a  crimson  flame. 

Thallium  is  very  soft  and  malleable. 

Thorium  is  an  extremely  rare  metal,  remarkable  for  taking 
fire  below  red  heat,  and  burning  with  great  brilliancy.  Neither 
the  metal  nor  its  compounds  are  of  practical  use ;  its  oxide 
has  the  high  specific  gravity  of  94. 

Titanium  is  a  rare  metal,  usually  obtained  in  crystalline 
form,  and  also  as  a  heavy  iron-gray  powder.  The  crystals  are 
copper-colored  and  of  extreme  hardness. 

Tungsten  is  a  hard,  iron-gray  metal,  very  difficult  of 
fusion.  An  alloy  of  ten  per  cent,  of  this  metal  and  90  per 
cent,  of  steel  is  of  extreme  hardness.  Both  the  metal  and 
its  compounds  have  proved  of  value  alloyed  in  steel  and 
bronze. 

Uranium  is  very  heavy  and  hard,  but  moderately  mallea- 
ble, resembling  nickel  and  iron ;  it  is  unaltered  at  ordinary 
temperatures  by  air  or  water. 

Rubidium  and  caesium  so  closely  resemble  platinum  that 
no  ordinary  test  will  distinguish  them. 

Indium  is  very  soft,  malleable  and  fusible  ;  it  marks  paper 
like  lead. 

Barium,  cerium,  columbium  (or  niobium),  didymium,  lan- 
thanium,  tantalum,  terbium,  yttrium,  and  zirconium,  are  all 
rare  metals  and  not  very  well  known. 

59.  The  Commercial  Metals  are  never  chemically  pure. 
Lake  Superior  copper  and  the  best  lead  and  tin  are  practi- 
cally so,  but  all  other  metals  have  such  a  variety  of  quality 
and  composition,  as  sold  in  our  markets,  that  the  purchaser 
and  consumer  can  only  rely  upon  careful  analyses  to  deter- 
mine their  value  for  any  proposed  use.  This  precaution  is 


100  MATERIALS  OF  ENGINEERING—NON-FERROUS  METALS. 


especially  advisable  when  the  engineer  selects  metals  of 
alloys  for  use  in  construction. 

Thus  copper  has  been  found  to  contain  as  much  as  30 
per  cent,  lead  and  8  or  9  per  cent,  of  nickel,  iron,  arsenic, 
and  other  metals  ;  lead  often  contains  several  per  cent,  of 
antimony,  arsenic,  zinc,  and  other  elements ;  iron  may  con- 
tain besides  the  sulphur  and  phosphorus  which  frequently 
seriously  injure  it,  a  considerable  amount  of  manganese, 
chrome,  nickel  and  cobalt,  and  even  copper ;  platinum  often 
contains  appreciable  quantities  of  the  other  rare  metals,  as 
paladium,  rhodium,  usually  iridium  and  osmium,  and  some- 
times iron  and  copper ;  zinc  is  very  frequently  rendered  use- 
less for  the  engineer's  purposes  by  the  presence  of  lead. 

The  Prices  of  Metals  are  so  constantly  varying  that  no 
list  can  be  given  of  great  accuracy.  The  cost  of  reduction, 
the  relations  of  supply  and  demand,  and  the  accidental  fluctu- 
ations of  the  market  combine  to  determine  the  exact  figures. 
The  following  table,  calculated  by  Bolton,*  may  be  taken  as 
representing  approximate  values. 

PRICES  OF  METALS. 


METAL. 

STATE. 

VALUE  IN 
GOLD  PER  LB. 
AVOIRDUPOISE. 

PRICE  IN 
GOLD    PER 
GRAMME. 

AUTHORITY. 

Vanadium  . 

$J.  7Q2    J.O 

$10  80 

g 

Rubidium  

Wire 

3  261  60 

7    2O 

s 

Calcium 

2  446    2O 

5    JO 

Q 

Tantalum  . 

Pure 

2  446    2O 

SAO 

s 

Cerium  

Fused  globule 

2  446    2O 

SAO 

s 

Lithium 

2228    76 

s 

I>ithium 

Wire 

2Q-2C      A  A 

6  48 

s 

F^rbium  

Fused 

I  671    ^7 

306 

s 

Didymium  

1  630.08 

•3.60 

s 

Strontium. 

Electrolytic 

I   ^  76   AA 

o     18 

s 

Indium  

Pure 

I  52^    08 

3q6 

T 

Ruthenium  

I  "3O4   64 

2.88 

T 

Columbium  
Rhodium  

Fused 

1,250.28 
I  O^    8<1 

2.76 

2    28 

S. 
T 

Barium  

O2J.    12 

2OA 

s 

Thallium  

7^8    ^Q 

I    6l 

T 

Osmium  

6C2    ^2 

1  .44 

T 

Palladium   

do8  ^o 

I    IO 

T 

*  Engineering  and  Mining  Journal,  Aug.  21,  1875. 


THE   PRICES   OF  METALS. 
PRICES  OF  METALS. — Continued. 


IOI 


METAL. 

STATE. 

VALUE  IN 
GOLD  PER  LB. 
AVOIRDUPOISE. 

PRICE  IN 
GOLD    PER 
GRAMME. 

AUTHORITY. 

SU66.5Q 

Si  o*? 

T 

434.88 

06 

T. 

Gold  

2QO    72 

Titanium  . 

Fused 

O-IQ      go 

ro 

Tellurium 

fi 

I  <j6      2O 

•5* 

ja 

.... 

Chromium  

« 

I  O6      2O 

-i-i 

Platinum. 

M 

TOO      -2T 

27 

Manganese 

<« 

A-Z.  jl 

1  08    72 

24 

T 

Molybdenum  

^4.  34 

.12 

T. 

Magnesium  

^Vire  and  tape 

AC     -3O 

IO 

T 

Potassium  

Globules 

22   6^ 

.OS 

T. 

Silver  

18.60 

Aluminum  * 

Bar 

16  30 

036 

s 

Cobalt 

Cubes 

12  68 

O28 

S. 

Nickel         

H 

3  80 

.008 

T. 

3.26 

.OO7 

T. 

Sodium 

q  26 

.OO7 

T. 

Bismuth    

Crude 

I.QC 

.OO43 

S. 

I.OO 

Antimony          .      . 

•*6 

T. 

Tin      

2< 

.22 

T^uppc.! 

.1C 

Zinc  

.  IO 

Lead  

.06 

Iron 

01  A- 

The  prices  of  many  may  be  considered  also  as  "  fancy 
prices,"  and  a  whole  pound  of  some  of  the  metals  named 
could  hardly  be  obtained  at  even  these  figures.  In  compiling 
the  table,  the  prices  of  the  rarer  metals  are  obtained  from 
TrommsdorfPs  and  Schuchardt's  price  lists ;  the  avoirdupois 
pound  is  taken  as  equal  to  453  grammes,  and  the  mark  as 
equal  to  24  cents  gold. 

It  is  evident  that  the  prices  of  the  metals  bear  no  relation 
to  the  rarity  of  the  bodies  whence  they  may  be  derived ;  for 
calcium,  the  third  in  the  list,  is  one  of  the  most  abundant 
elements. 

*  The  price  of  copper  fell  in  1885-86  to  10  cents  per  pound,  rising  in  1887, 
with  the  formation  of  a  "  syndicate,"  to  16,  in  1889  to  n  cents,  and  aluminum 
fell  to  §5  and  less. 


CHAPTER   III. 

PROPERTIES   OF   THE   ALLOYS.* 

60.  Properties  of  Alloys. — The  Author,  before  entering 
upon  the  researches  directed  by  the  Committee  on  Metallic 
Alloys  of  the  United  States  Board,  and  before  making  a  series 
of  experiments  on  the  characteristics  of  alloys,  as  a  proper 
introduction  to  the  work  instituted  a  somewhat  exhaustive 
examination  of  the  records  of  earlier  experiments  in  this 
direction. 

The  result  of  this  investigation  has  been  to  reveal  a  vast 
amount  of  information  on  the  chemical  and  physical  proper- 
ties of  the  alloys;  but  such  information  is  widely  scattered, 
and  authorities  do  not  always  agree.  Some  experiments  have 
been  made  upon  alloys  made  from  the  impure  commercial 
metals,  others  from  metals  rendered  chemically  pure  for  the 
purpose.  Again,  the  apparatus  used  has  not  always  been  of  the 
same  degree  of  accuracy,  and  this  has  produced  another  cause 
of  disagreement.  These  differences,  however,  are  usually  slight. 

It  is  evident  that  alloys,  being  composed  of  metallic  bodies, 
will  possess  all  the  physical  and  chemical  characteristics  of 
metals  ;  they  have  the  metallic  lustre,  are  more  or  less  ductile, 
malleable,  elastic,  and  sonorous,  and  conduct  heat  and  elec- 
tricity with  remarkable  facility.  In  retaining  these  proper- 
ties, however,  the  compound  is  so  modified  in  some  of  its 
qualities,  that  it  often  does  not  resemble  either  of  its  con- 
stituents, and  might,  consequently,  be  regarded  as  a  new 
metal,  having  characteristics  peculiar  to  itself.  This  is  espe- 
cially the  case  with  those  which  are  used  in  the  arts.  It  would 

*  Prepared  originally,  in  large  part,  and  with  the  assistance  of  Mr.  Wm. 
Kent,  M.E.,  for  the  Committee  on  Metallic  Alloys  of  the  United  States  Board, 
appointed  to  test,  iron,  steel,  and  other  metals.  See  Report,  Vol  I.,  1878. 


PROPERTIES  OF   THE  ALLOYS.  103 

almost  seem  that  there  is  no  department  of  the  arts  requiring 
the  use  of  metals  for  which  an  alloy  may  not  be  prepared 
possessing  all  the  requisite  qualities,  when  these  are  not  found 
in  the  original  metals.*  The  physical  properties  of  an  alloy  are 
often  quite  different  from  those  of  its  constituent  metals.  Thus 
copper  and  tin  mixed  in  certain  proportions,  form  a  sonorous 
bell-metal,  possessing  properties  in  which  both  metals  are 
deficient ;  in  another  proportion  they  form  speculum  metal, 
which  is  as  brittle  as  glass,  while  both  of  the  constituent 
metals  are  ductile.  It  is  impossible  to  predict  from  the  char- 
acter of  two  metals  what  will  be  the  character  of  an  alloy 
formed  from  given  proportions  of  each.  In  most  cases,  how- 
ever, it  will  be  found  that  the  hardness,  tenacity,  and  fusi- 
bility will  be  greater  than  the  mean  of  the  same  properties  in 
the  constituents,  and  sometimes  greater  than  in  either;  while 
the  ductility  is  usually  less,  and  the  specific  gravity  is  some- 
times greater  and  sometimes  less.t  The  color  is  not  always 
dependent  upon  the  colors  of  the  constituent  metals,  as  is 
shown  by  the  brilliant  white  of  speculum  metal,  which  con- 
tains 67  per  cent,  of  copper. 

Very  slight  modifications  of  proportions  often  cause  very 
great  changes  in  properties.  M.  Bischoff  \  states  that  he  can 
detect  the  deteriorating  effect  of  one  part  tin  upon  ten  million 
parts  of  pure  zinc,  and  the  writer  has  found  half  of  a  per 
cent,  of  lead  to  reduce  the  strength  of  good  bronze  nearly  one- 
half  and  to  affect  its  ductility  to  an  almost  equal  extent. 

It  is  not  a  matter  of  indifference  in  what  order  the  metals 
are  melted  in  making  an  alloy.  Thus,  if  we  combine  90  parts 
of  tin  and  10  of  copper,  and  to  this  alloy  add  10  of  antimony  ; 
and  if  we  combine  10  parts  of  antimony  with  10  of  copper, 
and  add  to  that  alloy  90  parts  of  tin,  we  shall  have  two  alloys 
chemically  the  same,  but  in  other  respects — fusibility,  tenacity, 
etc. — they  totally  differ.  In  the  alloys  of  lead  and  antimony, 
also,  if  the  heat  be  raised  in  combining  the  two  metals  much 
above  their  fusing  points,  the  alloy  becomes  harsh  and  brittle. 

*  Muspratt's  Chemistry,  vol.  I,  p.  533. 

f  Ure's  Dictionary,  vol.  I,  pp.  46-50. 

t  British  Assoc.  Reports,  2,  1870,  pp.  2OQ,  2IO. 


104  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Some  metallic  alloys  are  much  more  easily  oxidizable  than 
the  separate  metals.  An  alloy  of  tin  and  lead  heated  to  red- 
ness takes  fire  and  continues  to  burn  for  some  time.* 

In  regard  to  certain  physical  properties,  Matthiessenf 
remarks  that  the  metals  may  be  divided  into  two  classes: 

Class  A. — Those  metals  which  impart  to  their  alloys  their 
physical  properties  in  the  proportion  in  which  they  them- 
selves exist  in  the  alloy. 

Class  B. — Those  metals  which  do  not  impart  to  their 
alloys  their  physical  properties  in  the  proportion  in  which 
they  themselves  exist  in  the  alloy. 

The  metals  belonging  to  class  A  are  lead,  tin,  zinc,  and 
cadmium  ;  and  those  belonging  to  class  B,  in  all  probability, 
all  the  rest. 

The  physical properties  of  alloys  may  be  divided  into  three 
classes : 

I.  Those  which  in   all  cases   are   imparted   to  the  alloy 
approximately  in  the  ratio  in  which  they  are  possessed  by  the 
component  metals. 

II.  Those  which  in  all  cases  are  not  imparted  to  the  alloy 
in  the  ratio  in  which  they  are   possessed  by  the   component 
metals. 

III.  Those  which  in  some  cases  are  and  in  others  are  not 
imparted  to  the  alloy  in  the  ratio  in  which  they  are  possessed 
by  the  component  metals. 

As  types  of  the  first  class,  specific  gravity,  specific  heat, 
and  expansion  due  to  heat  may  be  taken ;  as  types  of  the 
second  class,  the  fusing  points  and  crystalline  form ;  and  as 
types  of  the  third  class,  the  conducting  power  for  heat  and 
electricity,  sound,  elasticity,  and  tenacity. 

61.  The  Chemical  Nature  of  Alloys. — The  chemical  nat- 
ure of  alloys  has  long  remained  a  disputed  point  among  scient- 
ists. The  question,  "Are  alloys  definite  chemical  compounds, 
solutions,  or  mechanical  mixtures?"  is  not  easily  answered. 
Several  authors  give  their  views  and  describe  their  methods 
of  making  experiments  to  settle  this  question,  but  there  still 

*  Ure's  Dictionary,  vol.  I,  p.  49. 

f  Jour.  Chem.  Soc.,  vol.  5,  1867,  pp.  201-220. 


PROPERTIES  OF   THE  ALLOYS.  IO5 

remains  a  wide  difference  of  opinion  in  regard  to  it.  Most 
writers  now  agree,  however,  in  considering  some  alloys  as 
chemical  compounds  and  others  as  mixtures,  but  they  differ 
as  to  whether  any  particular  alloy  is  the  one  or  the  other. 
Thus  Calvert  and  Johnson  *  consider  the  tin-copper  alloys 
definite  compounds,  while  Matthiessenf  claims  that  they  are 
"  solidified  solutions  of  one  metal  in  the  allotropic  modification 
of  the  other."  Musprattif  says: 

Many  alloys  consist  of  simple  elements  in  definite  or  equivalent 
proportions,  while  others  are  produced  from  compound  bodies,  and 
often  the  components  do  not  exist  in  the  ratio  of  their  chemical 
equivalents.  Metals,  in  forming  alloys,  do  not,  however,  combine 
indiscriminately  with  one  another ;  the  union  is  governed  by  the 
greater  affinities  which  some  of  them  manifest  for  each  other ;  just 
as,  in  the  chemistry  of  bases  and  acids,  a  predisposing  attraction 
determines  a  preference.  This  in  some  measure  proves  that  the 
alloys  are  not  mechanical  mixtures,  but  definite  chemical  com- 
pounds. It  is  remarkable  that  the  native  gold  found  in  auriferous 
sands  and  rocks  is  alloyed  with  silver  in  the  ratio  of  one  equivalent 
of  the  latter  to  four,  five,  six,  eight,  ten,  etc.,  equivalents  of  the 
former,  but  the  combinations  never  afford  results  indicative  of  the 
metal  being  united  in  fractional  parts  of  an  equivalent. 

Muspratt  further  says  that  another  proof  of  the  chemical 
combination  subsisting  is,  that  the  compound  melts  at  a  lower 
temperature  than  the  mean  of  its  ingredients ;  but  Mat- 
thiessen  §  argues  that  this  is  no  proof. 

Watts  1  remarks  that  most  metals  are  probably  to  some 
extent  capable  of  existing  in  combination  with  each  other  in 
definite  proportions ;  but  it  is  difficult  to  obtain  these  com- 
pounds in  a  separate  condition,  since  they  dissolve  in  all  pro- 
portions in  the  melted  metals,  and  do  not  generally  differ  so 
widely  in  their  melting  or  solidifying  points  from  the  metals 

*  Phil.  Trans.,  1858,  p.  363.  \  British  Assoc.  Rep.,  1863,  p.  47. 

\  Muspratt's  Chemistry,  vol.  I,  p.  534. 

§  British  Assoc.  Rep.  1853,  p.  42  ;  also,  Jour.  Chem.  Soc.,  vol.  5,  1867,  p. 
207. 

|  Watts'  Dictionary,  vol.  iii.  p.  942. 


106  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

they  may  be  mixed  with  as  to  be  separated  by  crystallization 
in  a  definite  condition. 

The  chemical  force  capable  of  being  exerted  between  different 
metals  may,  as  a  rule,  be  expected  to  be  very  feeble,  and  the  conse- 
quent state  of  combination  would  therefore  be  very  easily  disturbed 
by  the  influence  of  other  forces.  But  in  all  cases  of  combination 
between  metals,  the  alteration  of  physical  properties,  which  is  the 
distinctive  feature  of  chemical  combination,  does  not  take  place  to 
any  great  extent.  The  most  unquestionable  compounds  of  metals 
are  still  metallic  in  their  general  physical  characters,  and  there  is  no 
such  transmutation  of  the  individuality  of  their  constituents  as  takes 
place  in  the  combination  of  a  metal  with  oxygen,  or  sulphur,  or 
chlorine,  etc.  The  alteration  of  characters  in  alloys  is  generally 
limited  to  the  color,  degree  of  hardness,  tenacity,  etc. 

Messrs.  Calvert  and  Johnson,  about  the  year  1860,  made 
a  long  series  of  experiments  on  alloys  and  amalgams  made 
with  pure  metals,  with  the  hope  of  throwing  some  light  upon 
the  subject,  and  of  solving  the  question  "  Are  alloys  mixtures 
or  compounds  ?  "  They  believe  that  they  have  succeeded  in 
ascertaining:  First,  the  influence  which  each  additional 
equivalent  quantity  of  a  metal  exerts  on  another;  secondly, 
the  alloys  which  are  compounds  and  those  which  are 
simple  mixtures;  for  compounds  have  special  and  character- 
istic properties,  while  mixtures  participate  in  the  properties 
of  the  bodies  composing  them.  They  hold  that  the  bronze 
alloys  are  definite  compounds ;  for  each  alloy  has  a  special 
value  of  conductivity  of  heat,  and  also  its  own  specific  gravity, 
and  its  own  rate  of  expansion  or  contraction  ;  while,  on  the 
contrary,  the  alloys  of  tin  and  zinc  are  mixtures ;  for  they 
conduct  heat,  have  a  specific  gravity  and  expand  according 
to  theory,  or  according  to  the  proportions  of  tin  and  zinc 
which  compose  each  alloy.  Calvert  and  Johnson's  con- 
clusions are  chiefly  based  upon  their  experiments  on  the 
heat  conductivity  of  the  alloys.  Later  experiments,  made  by 
Matthiessen,*  on  the  conducting  power  of  electricity,  led  him 

*  British  Assoc.  Reports,  1863,  pp.   37-48. 


PROPERTIES  OF   THE  ALLOYS.  IO/ 

to  different  conclusions.  He  experimented  upon  upwards  of 
250  alloys,  all  made  of  purified  metals.  The  results  of  his 
investigations  are  published  in  a  paper,  "On  the  Chemical 
Nature  of  Alloys,"  from  which  is  transcribed  the  following 
classification  of  the  solid  alloys,  composed  of  two  metals, 
according  to  their  chemical  nature. 

1 .  Solidified  solutions  of  one  metal  in  another : 

The  lead-tin,  cadmium-tin,  zinc-tin,  leacl-cadmium,  and 
zinc-cadmium  alloys. 

2.  Solidified  solutions  of  one  metal  in  the  allot  ropic  modifi- 
cation of  another : 

The  lead-bismuth,  tin-bismuth,  tin-copper,  zinc-copper, 
lead-silver,  and  tin-silver  alloys. 

3.  Solidified  solutions  ofallotropic  modifications  of  the  metals 
in  each  other  : 

The  bismuth-gold,  bismuth-silver,  palladium-silver,  plat- 
inum-silver, gold-copper,  and  gold-silver  alloys. 

4.  Chemical  combinations  : 

The  alloys  whose  composition  is  represented  by  Sn5  Au, 
Sna  Au,  and  Au2  Sn. 

5.  Solidified  solutions  of  chemical  combinations  in  one  an- 
other : 

The  alloys  whose  composition  lies  between  Sn5Au  and 
Sn2  Au,  and  Sn2  Au  and  Au2  Sn.  . 

6.  Mechanical  mixtures  of  solidified  solutions  of  one  metal 
in  another  : 

The  alloys  of  lead  and  zinc,  when  the  mixture  contains 
more  than  1.2  per  cent,  lead  or  1.6  per  cent.  zinc. 

7.  Mechanical  mixtures  of  solidified  solutions  of  one  metal 
in  the  allotropic  modification  of  tJie  other  : 

The  alloys  of  zinc  and  bismuth,  when  the  mixture  con- 
tains more  than  14  per  cent,  zinc  or  2.4  per  cent,  bismuth. 

8.  Mechanical  mixtures  of  solidified  solutions  of  the  allo- 
tropic modifications  of  tlie  two  metals  in  one  another: 

Most  of  the  silver-copper  alloys. 

Matthiessen,  however,  does  not  claim  that  the  above 
classification  is  not  liable  to  exception.  He  was  obliged  to 
assume  that  some  of  the  metals  undergo  a  change,  or  are 


IO8   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

converted  into  an  allotropic  modification  in  the  presence  of 
another  metal,  in  order  to  explain  some  of  the  phenomena 
which  he  observed,  but  he  admits  that  until  the  allotropic 
modifications  have  been  isolated,  the  assumption  must  re- 
main an  hypothesis. 

To  conclude,  we  can  only  say  that  the  question  is  still 
unsettled.  From  the  marked  peculiarities  of  properties 
observed  in  a  few  of  the  alloys,  we  are  led  to  pronounce  them 
chemical  compounds.  Some  others,  we  must  admit,  are 
simple  mixtures,  or  rather,  solidified  solutions.  But  in 
regard  to  the  large  majority  we  are  still  in  doubt.  Further 
experiments  may  throw  more  light  on  the  subject,  but  it  is 
probable  that  with  the  larger  number  of  alloys  it  will  be 
found  impossible  to  discover  their  exact  chemical  nature. 

62.  Specific  Gravity. — The  specific  gravity  of  an  alloy  is 
rarely  the  mean  between  the  densities  of  each  of  its  constit- 
uents. It  is  sometimes  greater  and  sometimes  less,  indicat- 
ing, in  the  former  case  an  approximation,  and  in  the  latter 
a  separation  of  the  particles  from  each  other  in  the  process  of 
alloying.  This  subject  has  been  studied  by  several  writers, 
and  their  published  results  agree  quite  closely  in  regard  to 
some  of  the  alloys,  but  differ  in  regard  to  others.  These 
differences  may  be  accounted  for  by  the  differences  in  the 
apparatus  used  by  the  experimenters,  by  the  fact  that  some 
determinations  have  been  corrected  for  temperature  and  pres- 
sure of  the  atmosphere,  while  others  were  not ;  but  principally 
from  the  fact  that  several  of  the  alloys  are  liable  to  be  very 
deficient  in  homogeneity,  and  that  the  density  of  the  same 
alloy  will  vary  according  to  the  conditions  under  which  it  is 
formed,  as  being  cast  too  cold  or  too  hot,  cast  in  iron  or  in 
sand  moulds,  etc.  A  bar  cast  in  a  vertical  position  is  apt  to 
have  a  greater  specific  gravity  at  the  bottom  of  the  bar  than 
at  the  top.  Repeated  fusion  of  an  alloy  also  causes  changes 
in  its  density. 

It  is  common  among  authorities  who  publish  determina- 
tions of  specific  gravities  of  the  alloys,  to  give  the  calculated 
as  well  as  the  observed  specific  gravity.  The  calculated 
specific  gravity  is  that  which  the  alloy  would  have  if  there 


PROPERTIES  OF   THE  ALLOYS.  IOO, 

were  neither  expansion  nor  condensation  of  the  metals  during 
the  act  of  combination.  The  specific  gravities  should  be 
calculated  from  the  volumes  and  riot  from  the  weights.  Dr. 
Ure*  gives  the  rule  as  follows:  Multiply  the  sum  of  the 
weights  into  the  products  of  the  two  specific  gravity  numbers 
for  a  numerator,  and  multiply  each  specific  gravity  number 
into  the  weight  of  the  other  body  and  add  the  products  for 
a  denominator.  The  quotient  obtained  by  dividing  the  said 
numerator  by  the  denominator  is  the  truly  computed  mean 
specific  gravity  of  the  alloy.  Expressed  in  algebraic  language 
the  above  rule  is  — 


__ 
~  Pw  +  p  W 

where  M  is  the  mean  specific  gravity  of  the  alloy,  Wand  w  the 
weights,  and  P  and  /  the  specific  gravities  of  the  constituent 
metals. 

Clarke's  compilation  of  the  "  Constants  of  Nature,"  pub- 
lished by  the  Smithsonian  Institution,  contains  a  full  table 
of  specific  gravities  of  the  alloys,  with  the  names  of  about 
twenty-five  authorities.  Of  these,  the  principal  are  Mallet, 
Calvert  and  Johnson,  Matthiessen,  and  Riche. 

The  following  table  of  the  alloys  whose  density  is  greater 
or  less  than  the,  mean  of  their  constituents,  is  given  by  several 
writers  : 

TABLE    XVIII. 

ALLOYS   OF   ABNORMAL   DENSITY. 


Alloys,  the  density  of  which  is  greater  than 
the  mean  of  their  constituents. 

Alloys,  the  density  of  which  is  less  than  the 
mean  of  their  constituents. 

Gold  and  zinc. 

Gold  and  silver. 

Gold  and  tin. 

Gold  and  iron. 

Gold  and  bismuth. 

Gold  and  lead. 

Gold  and  antimony. 
Gold  and  cobalt. 

Gold  and  copper. 
Gold  and  iridium. 

Silver  and  zinc. 

Gold  and  nickel. 

Silver  and  tin. 
Silver  and  bismuth. 

Silver  and  copper. 
Iron  and  bismuth. 

*  Ure's  Dictionary,  6th  ed.  1872,  vol.  I,  p.  92. 


IIO  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE  XVIII.— Continued. 


Alloys,  the  density  of  which  is  greater  than 
the  mean  of  their  constituents. 

Silver  and  antimony. 
Copper  and  zinc. 
Copper  and  tin. 
Copper  and  palladium. 
Copper  and  bismuth. 
Lead  and  antimony. 
Platinum  and  molybdenum. 
Palladium  and  bismuth. 


Alloys,  the  density  of  which  is  less  than  the 
mean  of  their  constituents. 

Iron  and  antimony. 
Iron  and  lead. 
Tin  and  lead. 
Tin  and  lead. 
Tin  and  palladium. 
Nickel  and  arsenic. 
Zinc  and  antimony. 


Calvert  and  Johnson  agree  with  Matthiessen  in  giving  the 
density  of  the  alloys  of  lead  and  antimony  as  less  than  the 
mean  of  the  constituents,  and  Matthiessen  shows  the  alloys 
of  lead  and  gold  to  have  a  greater  density  than  the  mean  of 
their  constituents.  Some  alloys  of  tin  and  gold  and  of  bis- 
muth and  silver  are  shown  by  Matthiessen  to  have  a  greater, 
and  some  a  less,  density  than  the  mean  of  their  constituents, 
and  the  same  is  true  of  the  alloys  of  some  other  metals. 

63.  Fusibility. — A  remarkable  property  of  many  of  the 
alloys  is  their  great  fusibility.  In  nearly  all  cases  the  fusing 
point  of  an  alloy  is  lower  than  the  mean  of  its  constituent 
metals,  and  in  some  instances,  as  in  the  so-called  fusible 
alloys,  it  is  lower  than  that  of  either.  The  cause  of  this  fact 
has  not  been  definitely  ascertained.  Some  regard  it  as  a 
proof  that  the  alloy  is  a  distinct  chemical  compound,  but 
most  authorities  differ  from  this  view.  Matthiessen  *  sup- 
poses that  chemical  combinations  may  exist  in  the  fused 
mass,  which  suffer  decomposition  on  cooling  or  solidifying. 
He  says  that  the  low  fusing  points  admit  of  explanation  by 
assuming  that  chemical  attraction  between  the  two  metals 
comes  into  play  as  soon  as  the  temperature  rises,  and  the 
moment  the  smallest  portions  melt,  then  the  actual  chemical 
compound  is  formed  which  fuses  at  the  lowest  temperature, 
and  then  acts  as  a  solvent  for  the  particles  next  to  it,  and  so 
promotes  the  combination  of  the  metals  where  this  can  take 
place. 

*  British  Assoc.  Reports,  1863,  p.  42. 


PROPERTIES  OF   THE  ALLOYS.  Ill 

In  another  place*  Matthiessen  remarks  that  all  mixtures 
have  a  lower  fusing  point  than  the  mean  of  the  substances 
forming  the  mixture  ;  for  instance,  salt-water  solidifies  below 
zero,  and  a  mixture  of  the  chlorides  of  sodium  and  potassium 
fuse  at  a  lower  point  than  the  mean  of  the  fusing  points  of 
the  components. 

Some  alloys  have  been  observed  to  fuse  at  one  point  and 
solidify  at  a  lower  one  ;  for  exarriple,  the  tin-lead  alloys, 
which  all  solidify  at  181°  C.,  but  the  fusing  point  of  which 
varies  with  the  different  proportions  of  the  component  metals 
from  181°  C.  to  292°  C. 

Concerning  these  alloys,  Pillichody  f  remarks  as  follows : 

When  the  points  of  solidification  are  observed  by  immersing  the 
thermometer  in  the  melted  alloy,  it  usually  exhibits,  during  the 
passage  of  the  mass  from  the  liquid  to  the  solid  state,  two  stationary 
points.  This  effect  is  due  to  the  separation  of  one  or  other  of  the 
component  metals,  while  an  alloy  of  constant  composition  still  re- 
mains liquid.  This  alloy  corresponds  to  the  composition  Sn3  Pb. 
An  alloy  richer  in  lead  would  first  deposit  lead,  and  an  alloy  con- 
taining a  larger  proportion  of  tin  would  first  deposit  tin — the  alloy 
Sn3  Pb  remaining  liquid  for  a  longer  or  shorter  time,  and  ultimately 
solidifying  at  1 8 1  °  C.  This  temperature,  therefore,  corresponds  to  the 
lowest  melting  point  that  can  be  exhibited  by  an  alloy  of  tin  and  lead, 
a  larger  proportion  of  either  metal  causing  the  melting  point  to  rise. 

With  the  exception  of  the  alloys  of  tin  and  lead,  and  the 
fusible  alloys,  the  fusing  points  of  but  few  of  the  alloys  have 
been  determined.  An  accurate  pyrometer  for  temperatures 
above  red  heat  is  needed  for  this  purpose.  The  "  Constants 
of  Nature,"  while  it  has  the  specific  gravities  of  several 
hundred  alloys,  gives  the  melting  points  of  only  six,  exclusive 
of  the  fusible  alloys  and  those  of  lead  and  tin.  Mallet  :£ 
gives  the  relative  fusibility  of  the  several  alloys  of  copper  and 
tin  and  copper  and  zinc,  and  shows  that  their  fusibility  in- 
creases regularly  as  the  proportion  of  copper  in  the  alloy 
diminishes. 

*  Jour.  Chem.  Soc.,  vol.  5,  1867,  p.  2O7- 

f  Ibid.,  vol.  15,  1862,  p.  30. 

\Phil.  Mag.,  vol.  21,  1842,  pp.  66-68. 


112  MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS. 

Some  alloys  in  passing  from  the  liquid  to  the  solid  state 
do  not  change  at  once,  but  remain  for  some  time  in  a  pasty 
condition.  Their  temperature  of  solidification,  therefore, 
cannot  be  distinctly  recognized.  This  is  the  case  with  an 
alloy  of  the  composition  Bi2PbSn2,  which  is  fusible  in  boil- 
ing water,  but  which  remains  in  a  pasty  condition  through  an 
interval  of  several  degrees  of  temperature,  so  that  it  can  be 
handled  like  a  plaster. 

M.  Person*  made  experiments  upon  the  alloys  Bi3Pb2Sn2 
(D'Arcet's  alloy,  fusible  at  96°  C.),  Bi2PbSn2  (fusible  in  boil- 
ing water),  and  BiPbSn2  (fusible  at  145°  C.),  and  formed  the 
conclusion  that  it  is  possible  to  assign  in  advance  the  heat 
necessary  to  fuse  an  alloy,  if  that  required  to  fuse  each  of  its 
component  metals  is  known.  He  gives  the  formula  (160  +  t) 
S  —  /,  in  which  /  is  the  temperature  at  which  fusion  is 
effected ;  for  example,  332°  C.  for  lead  if  melted  alone,  but 
only  96°  C.  if  melted  in  D'Arcet's  fusible  alloy ;  /  is  the  ex- 
penditure of  heat  necessary  to  produce  the  fusion,  that  is,  a 
certain  number  of  calories  (i  calorie  —  3.96  British  thermal 
units)  variable  with  / ;  5  is  the  difference  of  the  specific  heats 
of  the  liquid  and  solid.  If  t  and  /are  known,  %  can  be  found. 
In  the  case  of  tin,  t  =  235,  /  =  14.3,  from  which  $  —  0.0362. 
Having  this  value  of  S,  it  is  easy  to  calculate  the  heat  neces- 
sary to  melt  tin  at  any  temperature  whatever,  for  instance  at 
96°  C.,  for  which  we  find  9.3  cal.  Making  the  same  calcula- 
tion for  bismuth  and  for  lead  we  find  7.382  and  2.7  cal.  It 
only  remains  to  take  these  numbers  in  the  proportion  in 
which  each  metal  exists  in  the  alloy,  which  gives  a  little  less 
than  6.3  calories,  which  differs  from  the  number  found  by 
experiment  (6  cats.}  only  0.3  cal. 

Nothing  appears  to  have  been  written  upon  this  branch 
of  the  subject  since  M.  Person's  paper  was  published,  but  it 
is  probable  that  if  the  investigation  was  pursued  further  our 
knowledge  of  the  causes  of  the  remarkable  fusibility  of  the 
alloys  would  be  much  increased. 

M.  Riche  f  has  determined  the  melting  points  of  certain 

*  Comptes  Rendus,  vol.  25,  1847,  pp.  444-446. 
t  Ann.  de  Chim.,  vol.  30,  1873,  p.  351. 


PROPERTIES  OF   THE  ALLOYS.  113 

alloys  of  tin  and  copper,  by  means  of  Becquerel's  thermo- 
electric pyrometer.  He  obtained  concordant  results  with  the 
alloys  SnCu3  and  SnCu4,  but  with  all  other  alloys  the  results 
differed  widely  among  themselves. 

W.  C.  Roberts,*  chemist  to  the  British  mint,  has  published 
a  series  of  determinations  of  the  melting  points  of  several 
alloys  of  silver  and  copper.  The  temperature  was  estimated 
by  finding  the  amount  of  heat  contained  in  a  wrought-iron 
cylinder  of  known  weight  which  was  dropped  into  the  melted 
alloy  while  in  the  furnace,  and  removed  as  soon  as  the  mass 
showed  signs  of  solidifying.  The  specific  heats  of  the  iron 
and  of  the  alloy  were  the  data  used  in  the  calculation.  The 
alloy,  composed  of  630.29  parts  of  silver  and  369.71  parts 
copper,  corresponding  to  the  formula  AgCu,  showed  the 
lowest  fusing  point,  or  846.8°  C. ;  that  of  pure  copper  being 
1330°  C.,  and  that  of  pure  silver  1040°  C. 

64.  Liquation. — Many  of  the  alloys  exhibit  the  phenom- 
ena of  liquation,  or  separation  of  the  mass  of  melted  metal 
in  the  act  of  solidification  into  two  or  more  alloys  of  different 
composition.  The  resulting  alloy,  or  mixture  of  alloys,  is  con- 
sequently deficient  in  homogeneity.  The  causes  of  this 
separation  are  as  yet  but  imperfectly  understood.  Some 
observations  seem  to  show  that  an  alloy  of  constant  com- 
position and  of  a  comparatively  high  fusing  point  solidifies 
first  in  crystals  disseminated  throughout  the  mass,  while  the 
remainder  of  the  melted  metal  remains  fluid  for  a  longer 
time,  and  finally  solidifies  around  and  among  these  crystals. 
This  fact  would  tend  to  prove  that  the  first  alloy  solidified 
was  a  distinct  chemical  compound,  but  it  has  been  shown 
that  crystals  of  exactly  the  same  appearance  have  been 
formed  from  two  metals  in  a  wide  range  of  proportions. 

The  different  circumstances  under  which  the  separated 
alloys  may  be  formed,  such  as  the  heat  of  the  metal  when 
poured  into  the  mould,  and  the  fact  of  slow  or  of  rapid  cooling, 
are  known  to  have  some  influence  upon  the  amount  of  liqua- 
tion, or  the  difference  of  composition  of  different  parts  of  the 
same  casting,  but  this  influence  is  not  exerted  upon  all  alloys 
*Proc.  Roy.  Soc.,  vol.  23,  1875,  pp.  481-495. 


114  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

in  the  same  direction,  some  alloys  being  affected  in  one  way 
and  some  in  another  by  the  same  manner  of  treatment.  The 
bronze  alloys,  such  as  gun-metal,  are  said  to  have  the  liqua- 
tion diminished  by  rapid  cooling.  When  the  mass  is  cooled 
slowly,  bronze  castings  often  show  in  the  interior  what  are 
called  spots  of  tin,  but  which  are  really  spots  of  a  white  alloy 
of  copper  and  tin,  containing  a  larger  percentage  of  tin  than 
the  average  of  the  whole  casting.  When  slowly  cooled,  also, 
the  bottom  of  the  casting  is  often  found  to  contain  a  larger 
percentage  of  copper  than  the  top.  When  cooled  rapidly, 
however,  as  shown  in  the  experiments  of  General  Uchatius* 
in  casting  cannon  in  chilled  moulds,  the  liquation  is  reduced 
to  a  minimum,  and  the  resulting  alloy  is  more  homogeneous. 

Levol  f  made  some  experiments  on  the  liquation  of  the 
alloys  of  silver  and  copper,  and  concluded  that  the  only 
homogeneous  alloy  of  these  two  metals  was  the  one  whose 
composition  is  718.97  parts  of  silver  and  281.07  parts  of  cop- 
per, corresponding  to  the  formula  Ag3Cu2,  and  that  all  the 
others  are  liable  to  more  or  less  liquation.  It  has  lately  been 
shown,  however,  by  Mr.  W.  C.  Roberts,  \  chemist  to  the 
British  mint,  that  this  alloy  is  only  homogeneous  when  cooled 
rapidly.  If  the  cooling  is  slowly  effected,  its  homogeneity  is 
disturbed,  the  external  portions  being  slightly  richer  in  silver 
than  the  centre. 

Mr.  Roberts  made  several  determinations  of  the  liquation 
of  other  alloys  of  silver  and  copper,  and  found  that  the 
arrangement  of  an  alloy  is  to  a  great  extent  dependent  on 
the  rate  at  which  it  is  cooled,  and  that  several  alloys  of  silver 
and  copper  are,  under  suitable  conditions,  as  homogeneous  as 
Level's  alloy.  The  alloy  of  925  parts  silver  and  75  parts 
copper  was  found  to  be  nearly  homogeneous  when  cooled 
very  slowly,  the  composition  of  the  corners  and  centre  of  a 
cube  45  millimetres  on  a  side  showing  a  maximum  difference 
of  only  1.4  parts  in  1,000,  while  the  same  when  cooled  rapidly 
showed  a  difference  of  12.8  parts  in  1,000. 

*  Ordnance  Notes  No.  xl.  Washington,  D.  C.,  1875. 
f  Ann.  de  Chim.,  vol.  36,  1852,  pp.  193-224. 
\  Proc.  Roy.  Soc.,  vol.  23,  1875,  pp.  481-495. 


PROPERTIES  OF   THE  ALLOYS.  11$ 

Col.  J.  T.  Smith  *  relates,  in  reference  to  some  experiments 
made  by  him  on  the  alloy  of  silver  and  copper  containing 
91^3  per  cent,  of  silver,  that  the  separation  of  the  constituent 
parts  of  the  alloy  was  not  so  much  due  to  the  rapidity  or 
slowness  with  which  the  heat  of  the  fluid  metal  was  abstracted, 
as  to  the  inequality  affecting  its  removal  from  the  different 
parts  of  the  melted  mass  in  the  act  of  consolidation.  Thus,  if 
a  crucible  full  of  the  melted  alloy  were  lifted  out  of  the  furnace 
and  placed  on  the  floor  to  cool,  the  surface  of  the  melted 
metal  within  it  being  well  covered  with  a  thick  layer  of  hot 
ashes,  the  lower  parts  of  the  mass  after  it  had  become  solid 
would  be  found  to  contain  less  silver  in  proportion  than  the 
upper  surface. 

If,  on  the  other  hand,  the  crucible  were  left  to  cool  while 
imbedded  in  the  furnace,  the  upper  surface  being  exposed  to 
the  air,  then  the  lower  parts  would,  after  solidification,  be 
found  finer  than  the  upper  surface. 

Riche  f  has  made  several  experiments  on  the  liquation  of 
the  alloys  of  copper  and  tin.  He  remarks  that  to  manifest 
the  property  of  liquation,  it  is  necessary  to  agitate  the 
crucible  containing  the  melted  alloy,  at  the  moment  of  solidi- 
fication, in  order  to  separate  the  small  crystals  already  formed. 
The  results  obtained  on  the  last  product,  remaining  liquid  in 
a  mass  weighing  1,000  to  1,200  grammes,  showed  a  remarka- 
ble liquation  of  all  the  alloys  of  copper  and  tin  except  those 
corresponding  to  the  formulae  SnCu3  and  SnCu4 

Several  other  alloys  exhibit  like  phenomena  to  an  even 
greater  extent  than  those  above  mentioned.  Matthiessen 
and  Von  Bose  experimented  upon  alloys  of  lead  and  zinc 
and  bismuth  and  zinc,  melting  the  metals  together  in  various 
proportions,  and  found  that  one  end  of  a  bar  would  have  an 
excess  of  one  metal  and  the  other  end  an  excess  of  the  other. 
Alloys  of  copper  and  lead  containing  an  excess  of  lead  show 
a  liquation  in  a  remarkable  degree,  the  excess  of  lead  partly 
oozing  out  from  the  mass  on  cooling. 

*  Proc.  Roy.  Soc.,  vol.  23,  1875,  PP-  433~435- 

\  Comptes  Rendus,  vol.  67,  1868,  pp.  1138-1140,  and  vol.  30,  1873,  pp. 
35I-4I9- 


Il6  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

65.  Specific  Heat. — The  published  determinations  of  the 
specific  heat  of  the  alloys  are  not  numerous.     This  results, 
not    from    any   difficulty   of   making   the    observations,    but 
probably  because  they  have  not   been   considered   of   such 
practical  importance  as  those  of  other  properties,  and  partly, 
also,  because  M.  Regnault's  *  determinations,  made  in   1841, 
and  his  deductions  therefrom,  are  accepted  as  final. 

M.  Regnault  determined  the  specific  heat  of  two  classes 
of  alloys  ;  first,  those  which  at  100°  C.  are  considerably  re- 
moved from  their  fusing  points  ;  and,  secondly,  those  which 
fuse  at  or  near  100°  C.  The  specific  heats  of  the  first  series 
were  so  remarkably  near  to  that  calculated  from  the  specific 
heats  of  the  component  metals  that  he  announced  the  fol- 
lowing law : 

"  The  specific  heat  of  the  alloys,  at  temperatures  considerably 
removed  from  their  fusing  point,  is  exactly  the  mean  of  the 
specific  heats  of  the  metals  which  compose  them." 

The  mean  specific  heat  of  the  component  metals  is  that 
obtained  by  multiplying  the  specific  heat  of  each  metal  by 
the  percentage  amount  of  the  metal  contained  in  the  alloy 
and  dividing  the  sum  of  the  products  for  each  alloy  by  100. 

A  curious  fact  discovered  in  regard  to  these  alloys  is  also 
that  the  product  of  the  specific  heat  of  each  alloy  by  its 
atomic  weight  is  sensibly  constant,  varying  in  the  whole  series 
only  from  40.76  to  42.05. 

The  second  series  of  alloys,  or  those  which  fuse  at  a 
temperature  at  or  near  100°  C.,  show  a  wide  divergence  from 
the  above  law,  the  specific  heats  of  all  of  these  being  much 
higher  than  that  calculated  from  their  constituents.  The 
product  of  the  specific  heats  by  the  atomic  weights  varied 
also  from  45.83  to  72.97. 

Matthiessen  f  describes  a  simple  arrangement  of  the  dif- 
ferential thermometer  for  the  purpose  of  showing  that  the 
specific  heat  of  an  alloy  is  the  same  as  the  mean  of  those  of 
its  components. 

66.  Expansion  by  Heat. — The  expansion  of  the  alloys  by 

*  Ann.  de  Chini.,  vol.  I,  1841,  pp.  129-207. 
\  Jour.  Chem.  Soc.,  vol.  5,  1867,  p.  205. 


PROPERTIES  OF   THE  ALLOYS.  1 1/ 

heat  has  been  examined  by  Messrs.  Calvert  and  Lowe,  *  with 
a  view  to  learn  whether  their  expansion  followed  the  law  of 
the  proportions  of  their  components.  Four  series  of  alloys 
were  examined,  namely,  those  of  zinc  and  tin,  lead  and  anti- 
mony, zinc  and  copper,  and  copper  and  tin.  In  each  case 
the  expansion  was  less  than  that  deduced  by  calculation  from 
their  equivalents. 

In  alloys  of  copper  with  tin,  it  was  found  that  where  only 
a  small  quantity  of  tin  entered  into  the  composition  of  a  bar, 
the  expansion  fell  considerably  below  that  of  pure  copper, 
although  the  tin  added  has  a  much  higher  rate  of  expansion 
than  copper. 

From  experiments  made  by  Messrs.  Calvert  and  Lowe 
upon  the  expansion  of  chemically  pure  metals,  they  conclude 
that  a  very  small  proportion  of  impurity  has  a  marked  in- 
fluence upon  the  expansion.  Their  results  differed  largely 
from  those  of  other  experimenters  who  used  only  the  com- 
mercial metals ;  but  when  they,  too,  used  commercial  metals, 
the  results  agree. 

The  alloys  upon  which  they  experimented  were  also 
formed  from  pure  metals,  and  on  account  of  the  difficulty  of 
procuring  these  in  sufficient  quantity,  the  bars  experimented 
on  were  very  small,  being  only  60  millimetres,  or  less  than  2*/2 
inches  long.  The  apparatus  used,  however,  as  described  at 
length  in  the  Chemical  News,  was  so  sensitive,  that  an  ex- 
pansion of  -JQ-O  OT  °f  an  mcn  could  readily  be  observed. 

If  experiments  were  made  upon  alloys  formed  from  the 
ordinary  commercial  metals,  it  would  probably  be  found  that 
their  rate  of  expansion  would  differ  considerably  from  that 
of  alloys  formed  from  pure  metals. 

The  molecular  condition  of  a  metal  was  observed  to  have 
an  important  influence  on  the  rate  of  expansion.  The  same 
will  no  doubt  be  found  true  in  the  case  of  alloys. 

Matthiessenf  states  that  the  expansion  due  to  heat  of  the 
metals  takes  part  in  that  of  their  alloys  approximately  in  the 
ratio  of  their  relative  volumes.  He  gives  a  table  of  the 

*  Chem.  News,  vol.  3,  1861,  p.  315. 

\  Jour.  Chem.  Soc.,  vol.  5,  1867,  p.  206. 


Il8  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

expansion  of  several  alloys  which  tends  to  confirm  his  state* 
ment. 

67.  Conductivity  for  Heat— The  power  of  the  alloys  to 
conduct  heat  has  been  examined  with  great  care  by  several 
experimenters.  The  published  results  are  not  always  con- 
cordant, but  the  differences  may  be  partially  accounted  for 
by  the  various  kinds  of  apparatus  used,  and  the  great  influence 
which  small  impurities  and  changes  in  molecular  condition 
and  crystalline  form  exert  upon  conductivity. 

The  conducting  power  for  heat  in  an  alloy  is  found  in 
some  cases  to  be  the  mean  of  the  conducting  power  of  the 
component  metals,  and  in  others  to  apparently  have  no  relation 
whatever  to  such  mean.  As  examples  of  the  first  case  may  be 
cited  the  alloys  of  tin  and  zinc  and  tin  and  lead;  and  of  the 
second,  the  alloys  of  gold  and  silver  and  gold  and  copper. 
From  this  circumstance  it  has  been  expected  that  the  heat- 
conducting  power  could  be  used  as  a  means  of  determining 
whether  an  alloy  is  a  chemical  compound  or  a  simple  mixture. 
As  before  stated,  however,  the  authorities  differ  widely  on 
this  point. 

Messrs.  Weidemann  and  Franz,*  in  1853,  made  some 
experiments  on  the  conducting  power  of  the  metals  and  of  a 
few  of  the  alloys,  using  a  thermo-electroscope  as  an  appa- 
ratus. 

In  1858,  Calvert  and  Johnson  t  made  an  extensive  research 
on  alloys  formed  from  pure  metals,  using  an  apparatus  of  their 
own  invention,  by  which  the  relative  conducting  power  was 
shown  by  the  rise  in  temperature  in  a  given  time  of  a  given 
volume  of  water  secured  in  a  box  at  one  end  of  the  bar,  while 
the  other  end  of  the  bar  was  heated  to  90°  C.  They  claim 
that  the  method  which  they  employed  gave  such  consistent 
results,  that  they  were  able  to  determine  the  influence  exer- 
cised on  the  conducting  power  of  the  metals  by  the  addition 
of  I  or  2  per  cent,  of  another  metal,  and  also  to  appreciate 
the  difference  of  conductivity  of  two  alloys  made  of  the  same 
metals  and  only  differing  by  a  few  per  cent,  in  the  relative 

*  P°gg>  Annalen,  vol.  89,  1853,  pp.  497-531. 
\  Phil.  Trans.,  1858,  pp.  349-368. 


PROPERTIES  OF   THE  ALLOYS.  IIQ 

proportions  of  the  metals  composing  them.  They  found  also 
that  the  conducting  power  of  metals  was  different  when  they 
were  rolled  out  into  bars  or  cast,  and  that  it  was  modified  by 
molecular  arrangement  or  position  of  the  axes  of  crystalli- 
zation, as  was  shown  by  the  different  conducting  power  of 
metals  cast  horizontally  and  vertically.  Some  curious  results 
were  observed  in  regard  to  alloys  of  gold  and  silver.  Silver 
being  the  best  conductor,  its  conductivity  is  rated  as  1,000, 
and  that  of  gold  the  next,  is  981  ;  but  gold  alloyed  with  I  per 
cent,  of  silver  has  a  relative  conductivity  of  only  840. 

The  conduction  of  heat  by  alloys,  according  to  Calvert 
and  Johnson,  may  be  considered  under  three  general  heads: 

1.  Alloys  which  conduct  heat   in   ratio   with   the  relative 
equivalents  of  the  metals  composing  them. 

2.  Alloys  in  which  there  is  an  excess  of  equivalents  of  the 
worse  conducting  metal  over  the  number  of  equivalents  of  the 
better  conductor,  such  as  alloys  composed  of  I  Cu  and  2  Sn,  I  Cu, 
and  3  Sn,  etc.,  and  which  present  the  curious  and  unexpected 
rule  that  they  conduct  heat  as  if  they  did  not  contain  a  particle 
of  the  better  conductor,  the  conducting  power  of  such  alloys 
being  the   same   as  if  the  bar  was  entirely  composed  of  the 
worse  conducting  metal.     A  not  less  remarkable  fact  is  that 
the  alloys  of  a  series,  such   as  those   of  2  equivalents  of  bis- 
muth and  I  of  lead,  3  Bi  and  I  Pb,  4  Bi  and  I  Pb,  all  conduct 
heat  alike,  the  various  increasing  quantities  of  lead  exercis- 
ing no  influence  on  the  conductivity. 

The  results  obtained  with  this  class  of  alloys  are  most  im- 
portant to  engineers ;  for  it  will  be  seen  in  the  case  of  alloys 
of  brass  and  bronze  that  no  increase  is  gained  in  the  con- 
ductivity of  an  alloy  by  increasing  the  quantity  of  a  good 
conductor;  nay,  in  many  cases  it  would  be  a  decided  loss, 
unless  a  sufficient  quantity  of  the  better  conducting  metal  be 
employed  to  bring  the  alloy  under  the  third  head. 

3.  Alloys  composed  of  the  same  metals  as  the  last  class,  but 
in  which  the  number  of  equivalents  of  the  better  conducting 
metal  is  greater  than  the  number  of  equivalents  of  the  worse 
conductor ;  for  example,  alloys  composed  of  I  Sn  2  Cu,  I  Sn 
3  Cu,  etc.     In  this  case  each  alloy  has  its  own  arbitrary  con- 


120  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

ducting  power ;  the  conductivity  of  such  an  alloy  gradually 
increases  and  tends  toward  the  conducting  power  of  the 
better  conductor. 

In  a  later  experiment  upon  the  conductivity  of  mercury 
and  the  amalgams,  Calvert  and  Johnson*  discovered  that 
they  had  committed  an  error  in  their  first  experiments  in 
determining  the  conductivity  of  mercury,  by  disregarding  the 
fact  that  convection  of  the  liquid  increased  the  apparent  con- 
ductivity. In  the  first  experiments  they  found  the  apparent 
relative  conductivity  to  be  677,  silver  being  1,000;  but  in  the 
later  experiments  they  determined  the  real  relative  con- 
ductivity to  be  only  54,  or  less  than  that  of  any  other  metal. 
In  regard  to  the  fluid  amalgams,  they  found  in  all  cases  that 
their  conductivity  was  nearly  the  same  as  that  of  pure  mer- 
cury. 

Weidemann,f  in  1859,  published  a  paper  in  which  he  calls 
in  question  the  accuracy  of  the  results  found  by  Calvert 
and  Johnson,  and  criticises  the  apparatus  used  by  them  and 
the  small  size  of  the  bars  upon  which  they  experimented.  He 
also  gives  the  results  of  some  experiments  which  he  has  made 
upon  the  conductivity  of  a  few  alloys. 

Matthiessen  \  describes  a  simple  apparatus  for  showing 
the  different  conductivities  of  alloys.  He  also  states  that  the 
conductivity  for  heat  furnishes  no  evidence  of  whether  an 
alloy  is  a  chemical  compound  or  a  mixture. 

68.  Conductivity  for  Electricity. —  The  conductivity  for 
electricity,  like  the  conductivity  for  heat,  is  one  of  the  prop- 
erties which,  in  some  alloys,  is  the  mean  of  that  of  the  com- 
ponent metals,  and  in  others  seems  to  have  no  relation  what- 
ever to  such  mean. 

There  have  been  a  large  number  of  experiments  made 
upon  the  electric  conductivity  of  the  alloys,  but  in  this,  as  in 
the  examination  of  other  properties,  with  widely  varying 
results.  In  the  first  place,  the  determinations  of  the  con- 
ducting powers  of  the  metals  themselves  are  far  from  agree- 

*  Phil.  Trans.,  1859,  PP-  831-835. 

t  P°gg-  Annalen,  vol.  108,  1859,  pp.  393-406. 

\  Jour.  Chem.  Soc.,vo\.  5,  1867, p.  213. 


PROPERTIES  OF   THE  ALLOYS.  121 

ing;  as,  for  instance,  the  conductivity  of  copper,  according 
to  different  experimenters,  is  given  at  numbers  ranging  from 
66  to  100,  pure  silver  being  100. 

Again,  Matthiessen  *  has  shown  that  small  traces  of  the 
metals,  and  especially  of  the  metalloids,  reduce  the  conduc- 
tivity of  copper  to  a  great  extent.  He  states  also,  that  there 
is  no  alloy  of  copper  which  conducts  electricity  better  than 
pure  copper,  and  that  the  fact  of  the  wires  experimented 
upon  being  annealed  or  hard  drawn  causes  a  marked  differ- 
ence in  the  values  obtained,  annealed  wire  being  a  better 
conductor  than  hard  drawn ;  and,  further,  that  temperature 
has  likewise  a  marked  influence,  the  metals  losing  in  conduct- 
ing power  as  the  temperature  increases. 

In  1833,  Professor  Forbes  f  published  the  statement  that 
the  order  of  conducting  powers  of  the  metals  for  heat  and  for 
electricity  is  the  same.  He  states,  as  a  general  conclusion, 
"  that  the  arrangement  of  metallic  conductors  of  heat  does 
not  differ  more  from  that  of  those  of  electricity  than  either 
arrangement  does  alone  under  the  hands  of  different  ob- 
servers." 

Twenty  years  later,  Weidemann  and  Franz  J  arrived  at  the 
same  conclusion  in  regard  to  brass  and  German  silver,  and 
Weidemann,§  in  1859,  concluded  tne  same  in  regard  to  alloys 
in  general.  Weidemann  and  Franz  remarked  that  whatever 
the  quality  may  be  upon  which  calorific  conduction  depends, 
the  close  agreement  of  the  figures  renders  it  exceedingly  prob- 
able that  the  same  quality  influences  in  a  similar  manner 
the  transmission  of  electricity;  for  the  divergence  of  the 
numbers  expressing  the  conductivity  for  heat  from  those  ex- 
pressing the  conductivity  for  electricity  are  not  greater  than 
the  divergences  of  the  latter  alone,  exhibited  by  the  results 
of  different  observers. 

The  most  extensive  series  of  investigations  upon  the 
electric  conductivity  of  alloys  has  been  made  by  Matthiessen. 

*  Phil.  Trans.,  1860,  pp.  85-92. 

f  Phil.  Mag.,  vol.  4,  1834,  p.  27. 

\  P°S&'  Annalen,  vol.  89,  1853,  pp.  497-531. 

§  Ibid.,  vol.  108,  1859,  pp.  393-407. 


122  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

His  results  are  published  in  the  following  papers:  <4  On  the 
Electric  Conducting  Power  of  the  Metals ;"  *  "  On  the  Elec- 
tric Conducting  Power  of  Alloys  ;"f  "  On  the  Influence  of 
Temperature  on  the  Electric  Conducting  Power  of  Alloys  ;"  \ 
"On  the  Thermo-Electric  Series  ;"§  "On  the  Effect  of  the 
Presence  of  the  Metals  and  Metalloids  upon  the  Electric 
Conducting  Power  of  Pure  Copper;"]  "On  the  Chemical 
Nature  of  Alloys."  1 

It  was  chiefly  from  these  researches  that  Matthiessen 
arrived  at  the  conclusions  in  regard  to  the  question  whether 
alloys  are  chemical  compounds  or  mixtures,  which  have 
already  been  given  under  the  head  of  the  chemical  nature 
of  alloys. 

Matthiessen's  examination  of  the  conductivity  of  copper, 
made  in  1860,  greatly  stimulated  the  refinement  of  the  metal 
used  in  telegraphy  and  led  to  a  gradual  improvement,  from 
a  conductivity  of  less  than  50  per  cent,  up  to  above  98  per 
cent.,  that  of  pure  copper  in  the  latest  work.  Good  wire  has 
highest  conductivity  when  soft,  but  the  strength  of  soft  cop- 
per is  often  much  less  than  one-half  that  of  hard  drawn  wire. 
Use  has  no  apparent  effect  on  conductors  of  this  metal,  but 
it  is  at  times  subject  to  a  peculiar  change  resulting  in  brittle- 
ness  and  loss  of  conductivity;  this  is  especially  liable  to 
occur  in  electro-magnets. 

In  regard  to  the  conducting  power  for  electricity  of  the 
alloys,  Matthiessen  divides  the  metals  into  two  classes : 

Class  A. — Those  metals  which,  when  alloyed  with  one 
another,  conduct  electricity  in  the  ratio  of  their  relative 
volumes. 

Class  B. — Those  metals  which,  when  alloyed  with  one 
of  the  metals  belonging  to  class  A,  or  with  one  another, 
do  not  conduct  electricity  in  the  ratio  of  their  relative 

*  Phil.  Trans.,  1858,  pp.  383-387. 
f  Phil.  Trans.,  1860,  pp.  161-176. 
\  Phil.  Trans.,  1864,  pp.  167-200. 
§  Phil.  Trans.,  1858,  pp.  369-381. 
|  Phil.  Trans.,  1860,  pp.  85-92. 
*f  British  Assoc.  Reports,  1863,  pp.  37-48. 


PROPERTIES  OF  THE  ALLOYS.  123 

volumes,  but  always  in  a  lower  degree  than  the  mean  of 
their  volumes. 

To  Class  A  belong  lead,  tin,  zinc,  and  cadmium.  To  class 
B  belong  bismuth,  mercury,  antimony,  platinum,  palladium, 
iron,  aluminium,  gold,  copper,  silver,  and  in  all  probability 
most  of  the  other  metals. 

69.  Crystallization.— The  crystallization  of  alloys  exhibits 
some  curious  phenomena.  It  was  formerly  supposed  that  if 
a  distinct  crystal  of  an  alloy  were  found,  it  would  have  a 
definite  chemical  composition,  and  would  show  that  the  alloy 
was  not  a  mixture,  but  a  veritable  chemical  compound. 

In  1854,  however,  Prof.  J.  P.  Cooke*  published  a  paper 
on  two  crystalline  compounds  of  zinc  and  antimony,  which 
exhibited  such  properties  as  justified  him  in  considering 
them  definite  chemical  compounds.  To  distinguish  them,  he 
gave  them  the  names  of  Stibiotrizincyle,  with  the  formula  Sb 
Zn3,  and  Stibiobizincyle,  with  the  formula  SbZn2.  In  the 
paper  named,  the  crystalline  form  and  other  properties  are 
fully  described. 

A  short  time  afterward  it  was  found  that  well-defined 
crystals,  like  those  described  as  SbZn3,  were  obtained  from 
the  alloys  containing  between  43  and  60  per  cent,  of  zinc ; 
and  even  in  alloys  of  a  higher  zinc  percentage  crystals  of  the 
same  form  were  still  seen,  although  they  were  no  longer  well 
defined.  In  the  alloys  containing  between  20  and  33  per 
cent,  of  zinc,  well-defined  crystals,  like  those  described  as  Sb 
Zna,  were  formed ;  and  finally,  there  separated  from  the 
alloys  containing  between  33  and  42  per  cent,  of  zinc,  thin 
metallic  plates,  which  evidently  belonged  to  the  same  crys- 
talline form,  f 

The  same  fact  has  been  observed  by  Matthiessen  and  Von 
Bose  $  in  regard  to  the  alloys  of  gold  and  tin,  namely,  that 
well-defined  crystals  are  not  limited  to  one  definite  propor- 
tion of  the  constituents  of  an  alloy,  but  are  common  to  all 
gold-tin  alloys  containing  from  43  to  27.4  per  cent,  of  gold. 

*  Am.  Jour.  Art  and  Set.,  vol.  18,  1854,  pp.  229-237. 

f  Ibid.,  vol.  20,  1855,  pp.  222-238. 

J  Proc.  Roy.  Soc.,  i86o-'62,  pp.  433-436. 


124  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

They  also  found  in  the  case  of  these  alloys  that  the  crystals 
and  the  mother  liquor  were  never  of  the  same  composition, 
the  percentage  of  gold  in  the  mother  liquor  being  much  below 
that  in  the  crystals. 

From  experiments  by  F.  H.  Storer,*  it  appears  that  the 
alloys  of  copper  and  zinc  yield  crystals,  sometimes  exhibiting 
distinct  octahedral  faces,  sometimes  in  confused  aggregates 
of  crystals,  but  all  of  octahedral  character,  and  bearing  a 
striking  resemblance  to  the  crystals  of  pure  copper  obtained 
by  fusion.  None  of  the  crystals  were  found  to  contain  a 
larger  proportion  of  either  metal  than  the  remainder  of  the 
molten  liquid  from  which  they  had  separated.  Storer  con- 
cludes that  all  the  alloys  of  copper  and  zinc  crystallize  in  the 
regular  system,  and  that  they  are  not  definite  atomic  com- 
pounds, but  merely  isomorphous  mixtures  of  the  two  metals. 

Calvert  and  Johnsonf  have  also  noticed  the  crystallization 
of  the  alloys  of  copper  and  zinc,  and  state  that  it  is  probable 
that  Cu2Zn  and  Cu3Zn  are  definite  compounds,  as  they  are 
perfectly  crystallized,  and  have  also  a  special  heat-conducting 
power  of  their  own.  They  state  that  the  most  splendid  of 
all  the  brass  alloys  is  the  alloy  CuZn,  which  is  of  a  beautiful 
gold  color,  and  crystallizes  in  prisms  often  3  centimetres  long. 

Slow  cooling  of  an  alloy  is  apt  to  favor  the  separate  crys- 
tallization of  one  or  more  of  its  components,  and  thus  render 
it  brittle.  Sometimes  in  casting  an  alloy  in  large  masses, 
there  will  be  a  partial  separation  of  the  constituents,  and 
crystals  of  different  composition  will  be  found  at  the  top  and 
bottom  of  the  mass,  those  at  the  bottom  usually  containing 
the  larger  percentage  of  the  metal  which  has  the  greater 
specific  gravity.  This  phenomenon  has  already  been  noted 
under  the  head  of  liquation. 

70.  Oxidation  and  Action  of  Acids. — But  few  experiments 
have  been  made  to  determine  the  rate  of  oxidation  or  cor- 
rosion of  the  alloys  by  atmospheric  influences  or  by  the  action 
of  acids.  It  is  generally  found  that  the  action  of  the  atmos- 
phere is  less  on  alloys  than  on  their  component  metals.  An 

*  "  Memoirs  of  the  American  Academy,"  vol.  8,  1863,  pp.  27-56. 
f  Phil.  Trans.,  1858,  p.  367. 


PROPERTIES   OF   THE  ALLOYS.  1 25 

instance  of  this  is  the  ancient  bronze  statues  and  coins,  some 
of  the  latter  of  which  have  their  characters  still  legible, 
although  they  have  been  exposed  to  the  effects  of  air  and 
moisture  for  upward  of  twenty  centuries. 

The  action  of  the  atmosphere  on  an  alloy  heated  to  a 
high  temperature  is  sometimes  quite  energetic,  as  is  shown 
in  the  alloy  of  three  parts  lead  and  one  of  tin,  which,  when 
heated  to  redness,  burns  briskly  to  a  red  oxide.  When  two 
metals,  as  copper  and  tin,  are  combined,  which  oxidize  at 
different  temperatures,  they  may  be  separated  by  continued 
fusion  with  exposure  to  the  air.  Cupellation  of  the  precious 
metals  is  a  like  phenomenon. 

Mushet*  found  that  unrefined  copper  resisted  the  action 
of  muriatic  acid  better  than  pure  copper.  This  he  thought 
was  due  to  the  presence  of  tin  in  the  unrefined  copper,  as  he 
found  that  an  alloy  of  copper  containing  about  3  per  cent,  of 
tin  resisted  the  action  of  acid  to  still  greater  extent.  The 
latter  he  recommends  for  the  purpose  of  ship-sheathing. 

Calvert  and  Johnsonf  have  made  several  experiments  to 
determine  the  action  of  nitric,  hydrochloric,  and  sulphuric 
acids  upon  alloys  of  copper  and  zinc  and  copper  and  tin. 
Some  of  the  results  thus  obtained  were  entirely  unexpected. 
Nitric  acid  of  1.14  specific  gravity  was  found  to  dissolve  the 
two  metals  in  an  alloy  of  zinc  and  copper  in  the  exact  pro- 
portion in  which  they  exist  in  the  alloy  employed,  while  an 
acid  of  1. 08  specific  gravity  dissolved  nearly  the  whole  of  the 
zinc  and  only  a  small  quantity  of  the  copper.  Hydrochloric 
acid  of  1.05  specific  gravity  was  found  to  be  completely 
inactive  on  all  alloys  of  copper  and  zinc  containing  an  excess 
of  copper,  and  especially  on  the  alloy  containing  equivalent 
proportions  of  each  metal.  Zinc  was  found  to  have  an  ex- 
traordinary preventive  influence  on  the  action  of  strong 
sulphuric  acid  on  copper. 

The  alloys  of  copper  and  tin  were  all  found  to  resist  the 
action  of  nitric  acid  more  than  pure  copper,  but  the  preven- 

*  Phil.  Mag.,  vol.  6,  1835,  pp.  444-447. 

t  Ibid.,  vol.  10,  1855,  pp.  250,  251  ;  also,  Jour.  Chem.  Soc.,  vol.  19,  1866, 
pp.  434-454- 


126  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

tive  influence  of  tin  presents  the  peculiarity  that  the  action 
of  the  acid  increases  as  the  proportion  of  tin  increases  ;  thus 
the  alloy  CuSn5  is  attacked  ten  times  more  than  the  alloy  Cu 
Sn.  The  alloys  SnCu2  and  SnCu3  were  attacked  by  strong 
sulphuric  acid  with  more  violence  than  an)/  other  of  the 
bronzes. 

Three  alloys,  viz.,  Cul8ZnSn,  CuIOZnSn,  and  Cu4Zn2, 
were  found  to  be  only  slightly  attacked  by  strong  nitric  or 
hydrochloric  acids,  and  not  at  all  by  sulphuric  acid.  The 
resistance  to  the  action  of  nitric  acid  is  remarkable,  as  its 
action  on  each  of  the  component  metals  is  very  violent. 

A.  Bauer  *  has  also  published,  in  the  Berichte  der  deut- 
schen  chemise/ten  Gesellschaft,  the  result  of  some  experiments 
on  the  action  of  hot  sulphuric  acid  on  several  alloys  of  lead. 
These  experiments  show  that  the  addition  of  a  little  antimony 
or  copper  renders  the  alloy  more  able  to  resist  sulphuric  acid, 
while  bismuth  has  a  decidedly  injurious  effect. 

71.  Hardness  and  other  Mechanical  Properties. — The 
mechanical  properties  of  the  alloys,  such  as  hardness,  mallea- 
bility, ductility,  resistance  to  strains  of  tension,  compression, 
and  torsion,  elasticity,  resilience,  etc.,  are  of  the  utmost  im- 
portance to  the  engineer,  but,  at  the  same  time,  it  is  most 
difficult  to  find  reliable  information  regarding  them.  But 
few  experimenters  of  authority  have  investigated  the  subject, 
and  their  researches,  although  valuable  as  far  as  they  go,  are 
too  limited  in  extent  to  allow  of  a  complete  classification  and 
comparison.  A  few  alloys  which  are  of  special  service  in  the 
arts  have  been  well  studied  by  those  who  have  had  occasion 
to  use  them,  with  a  view  to  learn  their  mechanical  properties, 
not  as  a  matter  of  scientific  interest,  but  as  an  actual  necessity. 
This  has  been  the  case  especially  with  the  various  gun-metals, 
upon  which  many  experiments  have  been  made  under 
authority  of  the  different  governments,  so  that  among  all  the 
alloys  our  knowledge  of  the  gun-metals  is  the  most  extensive 
and  accurate.  In  like  manner  the  properties  of  journal  and 
anti-friction  metals  have  been  investigated  by  those  who  are 
concerned  in  their  manufacture  and  use. 

*  Scientific  American,  vol.  33,  1875,  p.  135. 


PROPERTIES  OF   THE  ALLOtt^  12? 

With  these,  and  a  few  other  exceptions,  however,  our 
information  on  the  mechanical  properties  of  the  alloys  is  very 
meagre.  It  has  been  the  endeavor  of  the  Author,  as  far  as 
possible,  to  supply  this  manifest  want  by  a  series  of  experi- 
ments on  a  large  number  of  alloys,  testing  them  to  deter- 
mine their  mechanical  properties. 

The  hardness  of  some  of  the  alloys  has  been  investigated 
by  Calvert  and  Johnson.*  They  used  an  apparatus  for 
determining  the  hardness,  which  consists,  chiefly,  of  a  conical 
steel  point  of  a  certain  size,  which  is  pushed  into  the  material 
whose  hardness  is  to  be  determined  a  given  distance  by 
means  of  weights  applied  at  the  end  of  a  lever.  The  relative 
hardness  is  shown  by  the  weight  required  for  the  different 
materials. 

A  somewhat  similar  apparatus  was  used  by  Major  Wade  f 
in  determining  the  hardness  of  gun-metal,  but  he  used  a 
diamond-shaped  point  and  a  fixed  weight,  determining  the 
relative  hardness  by  the  distance  which  the  point  was  pushed 
into  the  metal.  General  Uchatius,J  in  experiments  for  the 
Austrian  Government,  used  an  indenting  tool,  which  was 
forced  into  the  metal  to  be  tested  by  a  weight  of  4.4  pounds 
falling  through  a  height  of  9^  inches.  The  shorter  the  cut 
made  by  the  indenting  tool,  the  greater  the  hardness. 

Mallet  §  in  1842,  in  his  experiments  on  the  alloys  of  cop- 
per and  tin  and  copper  and  zinc,  determined  their  tensile 
strength,  and  also  the  order  of  their  ductility,  malleability, 
and  hardness.  In  his  work  on  the  "  Construction  of  Artil- 
lery," |  published  in  1856,  the  same  author  discusses  the 
physical  and  mechanical  properties  of  gun-metal,  showing 
the  effects  of  sudden  and  of  rapid  cooling,  and  the  deteriorat- 
ing effect  of  small  proportions  of  a  third  metal,  such  as  iron, 
zinc,  lead,  or  antimony. 

In  regard  to  the  extent  of  our  knowledge  upon  these  sub- 

*  Phil.  Mag.,  vol.  17,  1859,  pp.  114-121. 

f  "  Report  of  Experiments  on  Metals  for  Cannon,"  Phila.,  1856. 

j  Ordnance  Notes  No.  XL.,  Washington,  D.  C,  1875. 

§  Phil.  Mag.,  vol.  21,  1842,  pp.  £6-68. 

|  Mallet,  "Construction  of  Artillery,"  London,  1856,  pp.  80-101. 


128  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

jects,  he  remarks :  "  Gun-metal,  probably  the  very  earliest 
used  material  for  cannon,  is  that  which  has  received  the  least 
improvement  or  systematization  of  our  knowledge  as  to  its 
use,  up  to  the  present  time ;  the  archaeologist  finds  the  rude 
weapons  of  Scandinavian,  Celtic,  Egyptian,  Greek,  and  Ro- 
man warfare  formed  of  nearly  the  same  alloys  of  copper  and 
tin,  and  in  about  the  same  proportions,  as  the  cannon  of  to-day." 

The  circumstances  of  chief  difficulty  and  importance  in 
the  manipulation  of  gun-metal,  as  affecting  the  production  of 
cannon,  are : 

1st.  The  chemical  constitution  of  the  alloy,  as  influencing 
the  balance  of  its  hardness,  rigidity,  or  ductility,  and  tenacity. 

2d.  Its  chemical  constitution,  and  what  other  conditions 
influence  the  segregation  of  the  cooling  mass  of  the  gun, 
when  cast,  into  two  or  more  alloys  of  different  and  often 
variable  composition. 

3d.  The  effects  of  rapid  and  of  slow  cooling,  and  of  the 
temperature  at  which  the  metal  is  fused  and  poured. 

4th.  The  effects  due  to  repeated  fusions,  and  to  foreign 
constituents,  in  minute  proportions,  entering  into  the  alloy. 

The  circumstances  of  manipulation,  as  above  named,  have 
already  been  shown  to  have  a  vast  influence  upon  nearly  all 
the  properties  of  the  alloys,  and  their  study  is  of  the  greatest 
importance,  not  only  in  reference  to  gun-metals,  but  to  all 
alloys  which  may  be  used  as  materials  of  construction. 

In  connection  with  the  subject  of  gun-metal,  the  experi- 
ments lately  made  by  General  Uchatius  *  for  the  Austrian 
Government  are  of  interest.  He  found  that  the  tenacity, 
elasticity,  and  hardness  of  bronze  were  increased  to  an  extra- 
ordinary degree  by  driving  a  series  of  conical  steel  mandrels 
or  plugs,  gradually  increasing  in  size,  into  the  bore  of  the 
gun.  The  metal  in  the  interior  of  the  gun  was  thus  stretched 
or  strained  much  beyond  its  elastic  limit,  and  was  thereby 
given  a  new  molecular  condition,  which  enables  it  better  to 
resist  both  the  expansive  force  of  the  exploded  powder,  and 
the  abrading  effects  of  the  shot. 

The  results  of  the  experiments  of  General  Uchatius  have 

*  Ordnance  Notes  No.  XL.,  Washington,  D.  C.,  1875. 


PROPERTIES  OF   THE  ALLOYS.  1 29 

been  communicated  to  the  Ordnance  Department  of  the 
United  States  by  Col.  T.  T.  S.  Laidley,  U.  S.  A.,  who  calls 
attention  to  the  fact  that  experiments  were  made  upon 
bronze,  with  a  view  to  improve  its  quality  for  guns,  by  Mr. 
S.  B.  Dean,  of  Boston,  in  1868-69,  at  which  time  he  used 
the  identical  mode  of  improving  the  bronze  adopted  by 
General  Uchatius  some  four  years  later.  Patents  for  the 
improvement  were  secured  in  May,  1869,  not  only  in  this 
country,  but  also  in  England,  France,  and  Austria.  The 
want  of  funds  rendered  it  necessary  for  Mr.  Dean's  experi- 
ments to  be  discontinued.  This  matter  will  be  considered  at 
greater  length  in  a  later  division  of  this  volume. 
9 


CHAPTER  IV. 

THE   BRONZES   AND   OTHER   COPPER-TIN  ALLOYS. 

72.  The  Alloys  of  Copper,  with  smaller  quantities  of  the 
more  common  metals,  are  the  most  valuable  and  the  most 
common,  and  the  most  extensively  used  of  all  compounds  or 
mixtures  known  to.  the  .engineer  and  the  metallurgist.  Those 
which  are  produced  by  the  union  of  copper  and  tin  are 
generally  classed  as  the  "  Bronzes."  When  copper  is  alloyed 
with  zinc,  the  composition  is  known  as  u  Brass."  These  terms 
are  not  exclusively  so  applied,  however,  and  the  term  brass  is 
not  infrequently  used  to  cover  the  whole  series  of  alloys  com- 
posed, wholly  or  in  part,  of  alloys  of  copper  and  tin,  copper  and 
zinc,  or  combinations  of  brass  and  of  bronze  with  each  other 
or  with  less  quantities  of  other  metals.  Bronzes  are  here  sup- 
posed to  contain  principally  copper  and  tin.  These  alloys  are 
produced  by  the  union,  either  chemically  or  by  solution,  when 
molten,  of  two  or  more  metals.  Nearly  all  metals  can  unite 
with  nearly  all  other  metals  in  this  manner,  and  the  number  of 
possible  combinations  is  infinite  ;  nevertheless,  but  few  alloys 
are  found  to  be  very  generally  used  in  the  arts.  It  is  consid- 
ered probable  that  the  metals  may  combine  chemically  in 
definite  proportions,  but  the  compounds  thus  produced  usually 
dissolve  in  all  proportions  in  either  of  the  constituents,  and  it 
is  rarely  possible  to  separate  the  chemically  united  portions. 
In  some  cases  the  affinity  is  very  slight,  as  between  lead  and 
zinc,  either  of  which  will  take  up  but  about  one  and  a  half  per 
cent,  of  the  other.  The  alloys  are  usually  the  more  stable  as 
their  constituents  are  the  more  dissimilar,  and,  when  this  dif- 
ference is  chemically  great,  the  compound  becomes  brittle. 
Occasionally,  an  alloy  is  formed  which  gives  evidence  of  the 
occurrence  of  chemical  union,  by  the  production  of  heat;  this 
is  seen  in  some  copper-zinc  alloys. 


BRONZES  AND  OTHER  COPPER  TIN-ALLOYS.  131 

Copper  alloys  are  formed  with  nearly  all  metals  with  great 
facility,  and  with  no  other  precaution  than  that  of  either 
preventing  access  of  oxygen  to  the  molten  mass,  or  of  thor- 
oughly fluxing  the  alloy,  to  take  up  such  as  may  have  com- 
bined with  it.  Many  of  these  alloys  were  once  considered 
chemical  compounds ;  but  the  view  which  seems  most  gener- 
ally accepted,  at  the  present  time,  is  that  they  are  almost  in- 
variably either  mere  mixtures,  or  that  a  species  of  solution  of 
the  one  metal  in  the  other  takes  place. 

The  most  minute  trace  of  foreign  element  often  produces 
an  observable,  or  even  an  important,  alteration  of  the  proper- 
ties of  copper.  This  is  especially  true  of  its  conductivity  for 
electricity,  which  is  reduced  greatly  by  an  exceedingly  minute 
proportion  of  iron  or  lead. 

73.  History. — The  alloys  of  these  metals  were  used  ex- 
tensively by  the  ancients  for  coins,  weapons,  tools  and  orna- 
ments, and  the  composition  of  their  bronzes,  as  shown  by 
recent  analyses,  indicates  that  they  were  as  skilful  in  brass- 
founding  as  the  modern  workman. 

Thus,  Phillips  gives  the  following  as  the  results  of  his  own 
examinations  and  as  showing  the  proportions  of  the  constit- 
uents employed  in  the  manufacture  of  brass,  at  times  bofh 
preceding  and  closely  following  the  Christian  era : 


DATE. 

i 

ZINC. 

TIN. 

LEAD. 

IRON. 

o 

u 

Large  brass  of  the  Cassia  family.  . 
"       Nero         M     .. 

B  C.     20 
A.D.    60 

82.26 
81.07 

17.31 
I7.8I 

•35 

1.05 

....  j 

"       Titus        "      .. 

"      79 

83.04!  15.84 

..... 

•  50 

"       Hadrian   "     .. 

"     I2O 

85.67 

10.85 

I.I4 

1-73 

•74 

Faustina  "     .. 

"     165 

79.14 

6.27 

4-97 

9.18 

•23 

Thus,  copper  and  zinc  were  the  essential  constituents  of 
the  alloys  examined  ;  but  then  lead  was  sometimes  present  in 
considerable  quantities,  together  with  tin  andiron.  Although 
zinc  occurs  in  such  considerable  quantities  in  these  alloys,  it 


132  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


was  not  known  in  the  metallic  state  until  about  the  thirteenth 
century,  when  it  was  described  by  Albert  of  Bollstadt. 

Many  analyses  of  ancient  articles  of  bronze  have  been 
made,  and  our  knowledge  of  this  very  old  alloy  is  consider- 
ably greater  than  that  of  the  alloys  of  zinc.  The  proportion 
of  the  constituent  metals  was  varied  according  to  the  purpose 
to  which  the  alloy  was  to  be  applied,  as  will  be  seen  from  the 
following  analyses,  the  hardness  being  modified  according  to 
the  proportion  of  tin  present.  The  alloys  containing  the 
largest  amount  of  tin  were  used  for  mirrors,  while  those  of 
medium  hardness  were  used  for  sword-blades  and  other  cut- 
ting instruments : 


COPPER. 

TIN. 

LEAD. 

IRON. 

COBALT. 

ANALYST. 

i.  Chisel,  from  ancient  Egyptian  quarry. 
2    Bowl  from  Nimroud 

94.00 

80    57 

5-90 



.10 

Wilkenson. 
Dr   Percy 

3.  Bronze  overlaying  iron  

88:37 

ii  33 

4.  Sword-blade,  Chertsey,  Thames  
5.  Axe-head  

89.69 
88  cs 

9-58 

II.  12 

'  '-78 

•33 

J.  A.  Phillips. 
Prof  Wilson 

6.  Celt  

81.19 

18.31 

78 

7.  Roman  As,  B.C.  500  

69.69 

7.16 

21.82 

•  47 

•57 

J.  A.  Phillips 

8.  Julius  Caesar  

8.00 

12.  8l 

•  The  third  specimen  was  analyzed  by  Dr.  Percy,  who  de- 
scribes it  as  a  small  casting  in  the  shape  of  the  foreleg  of  a 
bull,  forming  the  foot  of  a  stand,  consisting  of  a  ring  of  iron 
supported  upon  three  bronze  feet.  A  longitudinal  section 
disclosed  a  central  core  of  iron,  around  which  the  bronze  had 
been  cast. 

Some  writers,  to  account  for  the  immense  masses  of  hard 
stone  wrought  by  the  Egyptians  and  ancient  Americans,  sup- 
pose that  they  possessed  means  of  hardening  bronze  to  a 
degree  equal  to  that  of  our  steel;  this  requires  confirmation, 
since  no  remains  of  bronze  of  such  a  hard  variety  have  ever 
been  discovered. 

The  bronze  weapons  discovered  by  Dr.  Schliemann  among 
the  ruins  excavated  by  him  at  or  near  the  site  of  ancient 
Troy*  were  often  of  nearly  the  composition  of  modern  gun- 
bronze  ;  they  contained  copper  90  to  96,  tin  8.6  to  4.  The  date, 

*  "  Troy  and  its  Remains  ;"  London  and  New  York,  1875  ;  p.  361. 


BRONZES  AND  OTHER  COPPER-TIN  ALLOYS.  133 

archaeologically,  is  at  the  beginning  of  the  "  bronze  age,"  and 
immediately  at  the  close  of  the  "  stone  age."  Sir  John 
Lubbock  finds  the  bronze  implements  and  ornaments  of  the 
bronze  age  as  remarkable  for  their  beauty  and  variety  as  for 
their  utility.*  They  consisted  of  axes,  arrow-heads,  knives, 
swords,  lances,  sickles,  ear-rings,  bracelets,  rings,  etc.,  etc. 

The  bronze  used  by  the  prehistoric  nations  contained  no 
lead ;  that  of  the  Romans  and  post-Romans  was  rarely  of 
pure  copper  and  tin,  but  were  usually  more  or  less  alloyed 
with  lead.  Silver,  zinc,  and  lead  was  not  known  in  the 
bronze  age.  The  prehistoric  bronzes  were  cast,  sometimes  in 
metal  or  in  stone,  and  sometimes  in  sand,  moulds.  A  more 
common  method  was  by  wax  models,  or  "  patterns,"  which 
were  used  to  make  the  desired  cavity  in  an  earthen  or  sand 
mould,  the  wax  being  melted  out  afterward. 

According  to  Charnay,f  the  Aztecs  discovered  a  means  of 
tempering  copper,  and  of  giving  to  it  a  considerable  degree 
of  hardness,  by  alloying  it  with  tin.  Copper  hatchets  were 
known  among  them  ;  since  Bernal  Diaz  states  in  the  narrative 
of  his  first  expedition  to  Tobasco,  that  the  Spaniards  bartered 
glass-ware  for  a  quantity  of  hatchets  of  copper,  which  at  first 
they  supposed  to  be  gold.  Copper  abounded  in  Venezuela, 
and  we  still  find  there  in  great  numbers  trinkets  of  copper 
mixed  with  gold,  or  of  pure  copper,  representing  crocodiles, 
lizards,  frogs  and  the  like. 

In  cutting  down  trees,  they  employed  copper  axes  like 
our  own,  except  that,  instead  of  having  a  socket  for  the  haft, 
the  latter  was  split,  and  the  head  of  the  axe  secured  in  the  cleft. 

The  hatchet  described  seems  to  have  been  a  piece  of 
native  copper  wrought  and  fashioned  with  a  stone  ham- 
mer. The  Aztecs  made  good  bronze  chisels,  as  described 
by  Seftor  Mendoza,  director  of  the  National  Museum  of 
Mexico.  He  describes  certain  specimens  of  bronze  chisels 
belonging  to  the  collection  in  that  museum.  When  freed 
from  oxide  the  bronze  presents  the  following  characteristics: 
In  color  it  resembles  gold ;  its  density  is  8.875  '•>  Jt  is  malle- 

*  "  Prehistoric  Times  ;  "  London  and  New  York,  1872. 
f  N.  A.  Review,  1875  ;  Ruins  of  Central  America. 


134  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

able,  but  unlike  pure  copper,  is  hard,  and  breaks  under  strong 
tension  or  torsion  ;  the  fracture  presents  a  fine  granulation 
like  that  of  steel ;  in  hardness,  it  is  inferior  to  iron,  but  it  is 
sufficiently  hard  to  serve  the  purpose  for  which  it  was  in- 
tended. One  of  these  chisels  was  found  to  consist  of  copper 
97-87  per  cent.,  tin  2-13  per  cent.,  with  traces  of  gold  and 
zinc. 

The  bronzes  were  used  by  the  ancients  in  the  manufacture 
of  weapons  and  of  tools.  The  use  of  phosphorus  increases  the 
purity  and  adds  strength  and  hardness  to  these  alloys,  and 
the  remarkable  hardness  of  ancient  bronze  weapons  is  found 
by  Dr.  Reyer  to  be  due,  in  part  at  least,  to  the  presence  of 
phosphorus,  probably  introduced  with  the  flux  used  in  melt- 
ing. The  proportion  of  tin  varied  up  to  20  per  cent. 

74.  The  Alloys  of  Copper  and  Tin  have  many  uses  in  the 
arts.  The  two  metals  will  unite  to  form  a  homogeneous  alloy 
in  a  wide  range  of  proportions.  As  tin  is  added  to  pure  cop- 
per, the  color  of  the  alloy  gradually  changes,  becoming 
decidedly  yellow  at  10  per  cent,  tin  and  turning  to  gray  as 
the  proportion  approaches  30  per  cent.  In  the  researches 
conducted  by  the  Author,  it  was  found  that  good  alloys  may 
contain  as  much  as  20  per  cent.  tin.  When  the  color  changes 
from  golden  yellow  to  gray  and  white,  the  strength  as  suddenly 
diminishes  ;  and  alloys  containing  25  per  cent,  tin  are  valueless 
to  the  engineer;  nevertheless,  this  alloy  and  those  contain- 
ing up  to  30  per  cent,  show  compressive  resistances  increas- 
ing to  a  maximum.  The  tensile  and  compressive  resistances 
have  no  known  relation ;  the  torsional  resistance  is  more 
closely  related  to  tenacity. 

A  small  loss  of  each  constituent  occurs  in  melting,  the  loss 
often  being  highest  with  the  metal  present  in  the  lowest 
proportion  ;  this  loss  rarely  exceeds  one  per  cent.,  except  when 
the  fusion  has  taken  place  slowly  with  exposure  to  the  air,  when 
considerable  copper-oxide  is  liable  to  form.  The  specific 
gravities  of  these  alloys  do  not  differ  much  from  8.95. 

Under  17.5  per  cent,  tin,  the  elastic  limit  lies  between  50 
and  60  per  cent,  of  the  ultimate  strength ;  beyond  this  limit 
the  proportion  rises,  and  at  25  per  cent,  tin  the  elastic  limit 


BRONZES  AND  OTHER  COPPER-TIN  ALLOYS.  135 

and  breaking  point  coincide.  Passing  40  per  cent,  tin,  this 
change  is  reversed  and  the  elastic  limit,  although  indefinite, 
is  lowered  until  pure  tin  is  reached  and  a  minimum  at 
pjbout  30  per  cent. 

The  modulus  of  elasticity  of  all  the  bronzes  lies  between 
ten  and  twelve  millions. 

Riche  states  that  tempering  produces  on  steel,  forged  or 
annealed,  an  inverse  effect  to  that  which  it  produces  on 
bronzes  rich  in  tin ;  it  diminishes  its  density  instead  of  in- 
creasing it,  from  which  it  may  be  seen  that  tempering 
diminishes  the  density  of  annealed  steel  and  makes  it  hard, 
while  tempering  increases  the  density  of  annealed  bronze  and 
makes  it  soft. 

There  is  always  an  increase  in  density,  whether  the  bronzes 
rich  in  tin  be  tempered,  or  slowly  cooled,  after  compression. 

These  experiments  confirm  most  clearly  the  fact  affirmed 
by  D'Arcet,  that  tempering  softens  the  bronzes,  rich  in  tin, 
for  we  can  flatten  in  the  press  the  tempered  bronzes,  while  it 
is  impossible  to  do  this  with  steel. 

It  is  evident  from  his  experiments  that  tempering  aug- 
ments considerably  the  density  of  bronze  rich  in  tin,  and  that 
annealing  evidently  diminishes  the  density  of  tempered 
bronze.  Still  the  effect  of  slow  cooling  by  no  means  destroys 
the  effect  of  tempering,  for  the  density  continues  to  increase 
till  it  becomes  remarkable. 

While  all  mechanical  action  increases  the  density  of  the 
annealed  bronze,  it  very  slightly,  but  still  sensibly,  diminishes 
the  density  of  annealed  steel,  and,  on  the  whole,  tempering 
and  shock  increase  the  density  of  annealed  bronze,  while 
they  diminish  the  density  of  annealed  steel. 

But  the  variations  are  very  decided  for  bronze  and  very 
slight  for  steel. 

Bronze  of  96  and  97  parts  copper  may  be  employed  to 
great  advantage,  and  with  no  serious  inconvenience,  in  the 
manufacture  of  medals.  Its  hardness,  much  less  than  that  of 
the  alloy  of  M.  de  Puymaurin,  does  not  much  exceed  that  of 
copper ;  it  possesses  a  certain  sonority  and  casts  well,  rolls 
evenly,  and  its  color  is  more  artistic  than  that  of  copper. 


136  MATERIALS  OF  ENGINEERING—NON-FERROUS  METALS. 

The  action  of  the  press  and  of  heat  modify  its  density 
but  little. 

75.  Properties. — Copper  and  tin  alloy  in  all  proportions, 
and  the  most  useful  compounds  known  to  the  engineer  are 
the  "  bronzes,"  as  these  alloys  are  called.  They  include  gun- 
metal,  bell-metal  and  speculum  alloys.  The  following  is 
Mallet's  list  of  these  alloys  and  table  of  their  properties.* 

TABLE    XIX. 

PROPERTIES    OF   COPPER-TIN    ALLOYS. 
At.  wt.  :  Cu.  =  31.6  ;  Sn  =  58.9. 


AT.  COM  P. 

COPPER. 

S.  G. 

COLOR. 

FRACT. 

TENACITY. 

MALL. 

HARD. 

FUS. 

Cu  Sn 

per  ct. 

Tons  per  sq.  in. 

I         O 

too. 

8.607 

red-yellow 

24.6 

I 

IO 

16 

a  10 
b    9 

84.29 
82.81 

8.561 
8.462 

Xi 
yellow-red 

fine  grain 

16.1 
15.2 

2 

3 

8 
5 

15 
H 

c    8 

81.10 

8-459 

ifc 

lt 

17.7 

4 

4 

13 

d  7 

78.97 

8.728 

pale  red 

vitreous 

13.6 

5 

3 

12 

e    6 

76.29 

8.750 

" 

u 

9-7 

britrle 

2 

II 

f  5 

72.80 

8-575 

ash  gray 

conchoid. 

4-9 

" 

I 

IO 

i    4 
h    3 
i 

63.21 
61.69 

51-75 

8.400 

8.539 
8.416 

dark  gray 
white  gray 
white 

lam.  grain 

0.7 
0-5 
*-7 

friable 
brittle 

6 
7 
9 

I 

7 

j 

34  -92 

8.056 

vitreous 

1.4 

u 

ii 

6 

k 

21.15 

7-387 

lam.  grain 

3-9 

lt 

12 

5 

3 

T5-!7 

7-447 

" 

3-1 

8  tough 

J3 

4 

m           4 

11.82 

7.472 

** 

3-1 

6      " 

J4 

3 

»           5 

9  63 

7.442 

earthy 

2-5 

7 

J5 

2 

0     O        1 

o. 

7.291 

2.7 

16 

I 

a,  b,  c  are  gun-metals ;  d,  hard  brass  for  pins  ;  e,  f,  g,  h,  i,  bell-metal ;  /,  k,  for  small 
bells  ;  /.  m,  «,  o,  are  speculum  alloys. 

The  addition  of  a  small  quantity  of  tin  to  copper  causes  it 
to  become  brittle  under  the  hammer,  according  to  Karsten,  and 
the  ductility  is  restored  only  by  heating  to  a  red  heat  and 
suddenly  cooling.  Mushet  finds  that  the  alloy,  copper  97, 
tin  2,  makes  good  sheathing,  as  it  is  not  readily  dissolved  in 
hydrochloric  acid.  The  best  gun-metal  is  from  copper  90, 
tin  10,  to  copper  91,  tin  9  ;  if  richer  in  copper,  it  is  especially 
liable  to  liquation,  which  action  is  detrimental  to  all  these 
alloys.  Bell-metal,  copper  80,  tin  20,  to  copper  84,  tin  16,  is 
sonorous  and  makes  good  castings,  but  is  hard,  difficult  to 


*  Dingier 's  Journal,  Ixxxv.,  p.  378  ;  Watts's  Diet,  ii.,  p.  43. 


BRONZES  AND  0 TftER  COFFER- TIN  ALLOYS.  137 

work  and  quite,  brittle.  Suddenly  cooling  it  from  a  high 
temperature  reduces  its  brittleness,  while  slow  cooling  re- 
stores its  hardness  and  brittleness.  It  is  malleable  at  low 
red  heat  and  can  be  forged  by  careful  management. 

Speculum-metal,  copper  75,  tin  25,  is  harder,  whiter,  more 
brittle  and  more  troublesome  to  work  than  bell-metal. 

Old  flexible  bronzes  contain  about  %£  ounce  of  tin  to  the 
pound  of  copper,  or  copper  95,  tin  5,  as  stated  by  Ure. 
Ancient  tools  and  weapons,  as  shown  elsewhere,  contain 
from  8  to  15  per  cent,  tin ;  medals  from  8  to  12  per  cent.,  with 
often  2  per  cent,  zinc  to  give  a  better  color.  Mirrors  con- 
tained from  20  to  30  per  cent.  tin.  The  metals  mix  in  all 
proportions,  and  the  alloys  are,  to  a  certain  extent,  independ- 
ent of  their  chemical  proportionality.  The  occurrence  of 
hard,  brittle,  elastic  alloys  between  the  extremes  of  a  series 
having  soft  tin  and  ductile  copper  at  either  end,  both  of 
which  metals  are  inelastic,  is  probably  a  proof  that  these 
alloys  are  sometimes  chemical  compounds.  They  are  proba- 
bly, usually,  compounds  in  which  are  dissolved  an  excess  of 
one  or  the  others  of  the  components. 

76.  The  Principal  Bronzes  are  those  used  in  coinage,  in 
ordnance,  in  statuary,  in  bells,  and  musical  instruments,  and 
in  mirrors  and  the  specula  of  telescopes.  These  alloys  oxid- 
ize less  rapidly  than  copper,  are  all  harder,  and  often  stronger 
and  denser. 

Coin  bronze,  as  made  by  the  Greeks  and  Romans,  con- 
tained from  copper  96,  tin  4,  to  copper  98,  tin  2,  and  Chaudet  has 
shown  that  the  first  of  these  alloys  can  be  used  for  fine  work, 
obtaining  medals  of  this  composition  of  very  perfect  polish 
while  sufficiently  hard  to  wear  well.  Puymaurin  succeeded 
well  with  alloys  of  copper  93.5,  tin  6.5,  to  copper  90,  tin  10; 
and  Dumas  found  the  range  of  good  alloys  for  this  purpose 
quite  large,  varying  from  96  copper,  4  tin,  to  86  copper,  14  tin, 
but  the  best  falling  near  the  middle  of  this  range. 

Gun  bronze  has  various  compositions  in  different  countries. 
The  most  common  proportion  would  seem  to  be  copper  90, 
tin  10,  or  copper  89,  tin  11.  Well  made,  it  is  solid,  yellowish, 
denser  than  the  mean  of  its  constituents,  and  much  harder, 


138  MATERIALS  OF  ENGINEERING—  NOK-FERRO US  METALS. 

stronger,  and  more  fusible  than  commercial  copper;  it  is 
somewhat  malleable  when  hot,  much  less  so  when  cold. 

It  is  subject  to  some  liquation,  and  should  therefore  be 
quickly  chilled  in  the  mould ;  it  loses  some  tin  when  per- 
mitted to  stand  at  a  temperature  of  400°  to  500°  Fahr.  (200° 
to  260°  C.).  This  liquation  gives  rise  to  light-colored  spots 
throughout  the  metal.  This  bronze  does  not  readily  oxidize 
at  ordinary  temperatures,  but  is  quickly  attacked  when  hot ; 
it  usually  becomes  greenish  when  exposed  to  the  weather,  by 
the  formation  of  the  hydrated  carbonate ;  thus  "  patina  "  is  ob- 
served on  all  unpolished  old  bronze  guns  or  old  statues. 

Statuary  bronze  is  usually  of  nearly  the  same  composition 
as  gun-bronze.  It  should  be  rapidly  melted,  poured  at  high 
temperature,  and  quickly  cooled  to  prevent  liquation. 

Bell-metal  is  richer  in  tin  than  the  preceding,  and  varies 
in  composition  somewhat  with  the  size  of  bell.  The  propor- 
tion, 77  copper,  23  tin,  is  said  to  be  a  good  one  for  large  bells ; 
it  shrinks  0.015  in  the  mould  while  solidifying.  The  range 
of  good  practice  is  found  to  be  from  1 8  to  30  per  cent,  tin,  82 
to  70  per  cent,  copper ;  the  largest  proportions  of  tin  are  used 
for  the  smallest  bells,  and  an  excess  is  added  to  meet  the 
liability  to  oxidation  and  liquation;  copper  78-82,  tin 
22-18,  is  a  very  usual  composition.  When  made  of  scrap 
metal,  as  is  not  uncommon,  serious  loss  of  quality  is  liable  to 
occur  by  the  introduction  of  lead  and  other  metals  deficient  in 
sonorousness.  When  properly  made,  this  alloy  is  dense  and 
homogeneous,  fine-grained,  malleable  if.  quickly  cooled  in  the 
mould,  rather  more  fusible  than  gun-bronze,  but  otherwise  quite 
similar;  excelling,  however,  in  hardness,  elasticity  and  sonority. 

These  bronzes  become  quite  malleable  when  tempered 
by  sudden  cooling,  and  this  treatment  is  resorted  to  when 
they  are  to  be  subjected  to  prolonged  working  or  to  a 
succession  of  processes.  Chinese  gongs  are  made  of  copper 
78  to  80,  tin  22  to  20,  and  are  beaten  into  shape  with  the 
hammer,  the  metal  being  softened  at  frequent  intervals  by 
heating  to  a  low  red  heat  and  plunging  into  cold  water.  The 
tone  desired  is  obtained  by  hammering  the  instrument  until 
the  proper  degree  of  hardness  is  obtained.  Tempering  not 


BRONZES  AND  OTHER  COPPER-TIN  ALLOYS.  139 

only  increases  the  ductility  and  malleability  of  these  alloys, 
but  also,  it  is  claimed,  their  strength,  while  decreasing  their 
hardness  and  density,  when  they  are  made  into  thin  sheets; 
thick  plates  are  less  affected ;  annealing  by  slow  cooling  pro 
duces  an  opposite  effect. 

Speculum-metal  contains,  often,  as  much  as  33  per  cent, 
tin ;  it  is  steely,  almost  silvery  white,  extremely  hard  and 
brittle,  and  capable  of  taking  a  very  perfect  polish.  The  most 
suitable  proportion  of  tin  varies  slightly  with  the  character  of 
the  copper,  some  kinds  requiring  more  and  some  less  to  give 
the  degree  of  whiteness  and  the  perfection  of  polish  required. 
An  excess  of  tin  injures  the  color  and  reduces  the  lustre  of 
the  mirror. 

The  finest  speculum  metal  is  perfectly  white,  without  a 
shade  of  yellow,  sound,  uniform,  and  tough  enough  to  bear 
the  grinding  and  polishing  without  danger  of  disintegration. 
The  specula  made  by  Mudge  were  twice  fused,  and  con- 
tained from  32  parts  copper  and  16  tin  to  32  copper  and  14.5 
tin.  A  little  tin  is  lost  in  fusion.  According  to  David  Ross, 
the  best  proportions  are:  copper,  126.4;  tin,  58.9,  i.e.,  atomic 
proportions.  He  adds  the  molten  tin  to  the  fused  copper 
at  the  lowest  safe  temperature,  stirring  carefully,  and  secur- 
ing a  uniform  alloy  by  remelting,  as  is  often  done  in  making 
ordnance  bronze. 

Bronze  for  bearings  and  pieces  subject  to  severe  friction, 
as  in  machinery,  is  made  of  many  proportions.  Gun-bronze 
is  one  of  the  best ;  the  Author  has  known  of  one  case  in 
which  the  bronze  was  made  of  ingot  copper  90,  ingot  tin  10, 
and  used  in  the  main  crank-shaft  journal  of  a  steam  vessel  for 
ten  years  without  appreciable  wear,  although  the  area  was  not 
unusually  large  for  the  load  and  the  velocity  of  rubbing  was 
high,  as  is  usual  in  screw  engines.  The  proportions  given  in 
several  cases  will  be  found  elsewhere ;  they  vary  in  practice 
from  88  to  96  per  cent,  copper,  as  more  or  less  hardness  is 
required.  Bronze  for  steam  engine  packing  rings  is  some- 
times made  of  92  to  94  copper,  7  to  9  parts  tin,  I  part  zinc. 

77.  Old  Bronze. — According   to   Riche,*  the   analysis  of 

*  Appendix  to  U.  S.  Report  on  Tests  of  Iron  and  Steel,  vol.  i,  p.  556. 


140  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


antique  medals  shows  that,  though  the  ancients  sometimes 
used  copper  for  this  purpose,  they  ordinarily  employed  bronze 
in  which  the  proportion  of  tin  varied  between  wide  limits 
(from  I  to  25  per  cent.).  The  manufacture  of  medals  with  a 
bronze  rich  in  tin  is  not  practised  at  the  present  day,  on 
account  of  its  hardness,  and  because  considerable  relief  is 
necessary,  while  this  was  very  slight  in  the  medals  of  antiquity. 
Bronze  has  been  wholly  given  up  and  copper  substituted  for 
it ;  but  copper  also  presents  some  serious  inconveniences. 
It  rusts  badly,  does  not  ring  when  struck ;  its  red  tint  is  not 
artistic,  and  this  is  concealed  by  an  artificial  bronzing  which 
adheres  poorly,  and  which  causes  different  medals  to  vary  in 
tone. 

In  1828,  M.  dePuymaurin  made  a  large  number  of  experi- 
ments, and  continued  them  until  1832,  after  which  an  alloy  of 
94  copper,  4  tin,  and  2  zinc  was  adopted  in  France,  of  which, 
from  time  to  time,  medals  were  manufactured  until  1847,  at 
which  time  it  was  entirely  given  up  on  account  of  the  hard- 
ness of  the  metal  leading  to  a  deterioration  of  the  coin. 
Riche  advises  a  bronze  containing  96  or  97  per  cent,  copper, 
and  4  or  3  per  cent,  tin,  as  less  hard,  more  sonorous,  capable 
of  making  good  castings,  and  of  working  wrell  in  the  rolls, 
under  the  hammer,  or  in  the  dies;  it  has  also  a  good  color. 

78.  Oriental  Bronzes. — Analyses  of  Japanese  bronzes, 
made  by  M.  E.  J.  Maumene,*  give  the  following: 


NO.    I. 

NO.  2. 

NO.  3. 

NO.  4. 

CoDoer 

86  -38 

80   QI 

88  70 

Q2    O7 

Tin  

I  •  Q4 

7.  ec 

2    58 

I    O4. 

Antimony.            . 

I  61 

O   J.J. 

O    IO 

I    O4 

Lead  

*  68 

Srt1! 

<?      CA 

I    OJ. 

Zinc  

•5      -36 

3    O8 

q    71 

2    6* 

Iron 

o  67 

I    .13 

I    O7 

3  64 

Manganese       . 

o  67 

trace 

I    O7 

36d 

Silicic  acid  

O    IO 

o  16 

O   OQ 

o  04 

Sulphur      ...        .        . 

O    IO 

O    31 

O   OQ 

Waste  

o  26 

O    7Q 

O   21 

o  56 

100.00 

100.00 

IOO.OO 

100.00 

Comptes  Rendus>  1875. 


BRONZES  AND  OTHER  COPPER-TIN  ALLOYS. 


141 


These  alloys  are  all  of  a  granulated  texture,  blistered  on 
the  interior  surface,  sound  on  the  exterior  surface  (which  can 
be  readily  polished  with  a  file).  Their  color  is  sensibly  violet 
when  antimony  is  abundant,  red  when  iron  is  present.  All 
the  specimens  were  cast  thin,  from  0.195  to  0.468  inch,  and 
the  mould  was  well  filled.  It  appears  by  analysis  that  these 
alloys  were  not  made  with  pure  metals,  but  with  minerals. 
We  should,  says  Maumene,  consider  these  bronzes  as  result- 
ing from  the  use  of  copper  pyrites,  and  antimonial  galena 
mixed  with  blende ;  and  the  calcination  was  not  always  com- 
plete, as  the  presence  of  sulphur  in  specimen  No.  2  proves. 

Antique  alloys,  Greek,  Roman,  old  French,  etc.,  present 
similar  indications. 

79.  Density  of  Bronzes. — The  increase  of  density  above 
the  mean  of  the  densities  of  the  two  constituents,  probably 
either  due  to  the  affinity  of  the  metals,  or  freedom  from  air- 
cells,  is  exhibited  by  the  following  table,  prepared  by  Briche : 


ALLOY. 

S.  G.  ACTUAL. 

CALCULATED. 

DIFF. 

Cop 

per  i< 

X)  ;  t 

in     4 

8.79 
8.78 
8.76 
8.76 
8.80 

8.81 
8.87 
8.83 
8.79 

8.74 

8-71 
8.68 
8.66 
8.63 
8.61 
8.60 

8-43 
8.05 

0.05 
0.07 
0.08 
0.10 
0.17 
0.20 
0.27 
0.40 
0.74 

6  

8 

10     

14. 

16    

o-j 

IOO 

The  condensation  of  the  alloy,  due  to  the  affinity  of  its  con- 
stituents, or  to  greater  homogeneousness,  increases  as  the  pro- 
portion of  tin  increases  throughout  the  range  above  studied. 

80.  Ordnance  Bronze.— According  to  the  U.  S.  Ordnance 
Manual,  bronze  used  for  ordnance  consists  of  90  parts  of 
copper  and  10  of  tin,  allowing  a  variation  of  one  part  of  tin, 
more  or  less.  It  is  more  fusible  than  copper,  much  less  so 
than  tin,  more  sonorous,  harder,  and  less  susceptible  of  oxida- 
tion, and  much  less  ductile,  than  either  of  its  components. 
When  the  mixture  is  well  made,  the  metal  is  homogeneous ; 


142  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

the  fracture  is  of  a  uniform  yellow  color,  with  an  even  grain. 
The  specific  gravity  of  bronze  is  about  8.7,  being  greater 
than  the  mean  of  the  specific  gravities  of  copper  and  tin. 

Copper  proposed  to  be  used  in  ordnance  bronze  should 
be  condemned  for  the  manufacture  of  guns,  if  it  contains 
sulphur  in  an  appreciable  quantity ;  more  than  one-thou- 
sandth of  arsenic  and  antimony  united ;  more  than  about 
three-thousandths  of  lead,  iron,  or  oxygen  ;  if  it  contain  more 
than  about  five-thousandths  of  foreign  substances  altogether ; 
or  if,  near  these  limits,  it  give  bad  results  when  subjected  to 
the  mechanical  tests  of  hammering,  rolling,  and  wire-drawing. 

It  is  also  stated  that  tin  offered  should  be  rejected  if, 
when  run  into  elongated  drops,  it  have  not  a  smooth  and  re- 
flecting surface,  without  any  considerable  sign  of  rough  spots ; 
if,  when  analyzed,  it  contain  more  than  about  one-thousandth 
of  arsenic  and  antimony  united  ;  more  than  about  three- 
thousandths  of  lead  or  iron  ;  or  more  than  four-thousandths 
of  foreign  substances. 

All  bronze  ought  to  be  rejected  which  contains  sulphur  in 
an  appreciable  amount;  which  contains  more  than  about  one- 
thousandth  of  arsenic  and  antimony  united;  more  than 
about  three-thousandths  of  lead,  iron,  or  zinc;  or,  in  all, 
more  than  about  five-thousandths  of  foreign  substances. 

Notice  should  be  taken  of  the  appearance  of  the  fracture 
of  specimens  ;  it  sometimes  gives  indications  sufficient  to 
authorize  the  rejection  of  certain  bronzes  full  of  sulphur  or 
oxides. 

Gun-metal,  when  broken,  should  present  a  fine,  close- 
grained  fracture,  of  a  uniform,  beautiful  golden  color;  it  should 
be  ductile,  although  finely  granular  and  possibly  crystalline. 
Bronze  guns  often  exhibit,  when  burst,  a  decidedly  crystal- 
line surface,  the  axes  of  the  crystals  lying  radially  to  the  bore. 

According,  to  the  practice  of  the  Navy  Department,  the 
bronze  used  for  rifled  howitzers  is  composed  of  Lake  Superior 
copper  9  parts,  tin  I  part.  This  'is  used  when  the  casting 
is  made  in  a  sand  mould.  When  a  chill  mould  is  used,  which 
is  the  method  now  adopted  for  such  castings,  the  proportion 
is  changed  to  10  to  i. 


BRONZES  AND  OTHER  COPPER-TIN  ALLOYS. 


The  copper  is  melted  in  a  reverberatory  furnace,  and 
three  hours  after  the  fires  are  started,  when  the  copper  is  in 
perfect  fusion,  the  tin  is  stirred  in  ;  half-an-hour  after,  the 
bronze  is  run  off  into  the  moulds.  The  casting  cools  nat- 
urally, and  is  taken  out  of  the  mould  about  twenty-four  hours 
after  the  metal  is  run  in.  The  chill  mould  is  warmed  suf- 
ficiently to  drive  out  the  moisture. 

81.  Phosphor-Bronze  and  Manganese  Bronzes  are  alloys 
which  are  now  so  well  known  and  have  become  so  important 
in  the  arts  as  to  demand  special  notice. 

PJiosphor  bronze  has  been  known  many  years.  It  consists 
simply  of  any  alloy  of  bronze  or  brass  or  any  ternary  alloy  of 
copper,  tin  and  zinc  which  has  been  given  exceptional  purity 
and  excellence  by  skilful  fluxing  with  phosphorus.  It  is  also 
supposed  that  the  presence  of  phosphorus  is  useful  in  giving 
the  tin  a  crystalline  character  which  enables  it  to  alloy  itself 
more  completely  and  strongly  with  the  copper.  Phosphor- 
.bronze  will  bear  remelting  with  less  injury  than  will  common 
bronze.  The  phosphor  bronzes  greatly  excel  the  unphos- 
phuretted  alloy  in  every  valuable  commercial  quality,  and 
they  are  very  extensively  used  for  every  purpose  for  which 
such  alloys  are  fitted. 

The  following  are  Kirkaldy's  figures  for  tenacity  and 
ductility  of  phosphor-bronze  wire  of  No.  16  Birmingham 
gauge : 

PHOSPHOR-BRONZE  WIRE,  NO.   1 6,  B.  W.  G. 


MATERIALS. 

LOAD   AT   FRACTURE. 

c.S 
o 

'is  J? 

No.  twists  be- 

G bo 

fore  breaking. 

Unannealed. 

Annealed. 

.2  c 

Per  sq. 
mm. 

Per  sq  . 
in. 

Per  sq. 

mm. 

Per  sq. 
in. 

Per 
cent. 

Unan- 
nealed. 

An- 
nealed. 

72.3  kil. 

46  T. 

34.  7  kil. 

22  T. 

37  5 

6.7 

80 

Phosphor-bronze 
of    several    pro-  - 
portions. 

85.1 
85.2 
97-7 

112.  2 

54 
54-1 
62.1 
71  2 

33-6 

37-5 
42.8 

41.7 

21.3 
23.8 
27.2 
26.5 

34-1 
42.4 
44.9 
46.6 

22.3 
13.0 
17-3 
13-3 

52 

124 

§ 

106.3 

67.6 

45-4 

28.9 

42.8 

15-0 

60 

144  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

CAST   PHOSPHOR-BRONZE. 


REDUCT.    OF    SEC- 
TION. 

ELASTIC    LIMIT. 

ULTIMATE   RESISTANCE. 

Per  cent. 

Per.  sq.  mm. 

Per  sq.  in. 

Per  sq.  mm. 

Per  sq.  in. 

8.4 
i-5 
33-4 

16.05  kil- 

17-38 
II.  6 

10.6    T. 
11.05 

7.2 

37-0 
32.5 
3i-3 

23-  5  T. 
20.  6 
19.9 

The  phosphorus  is  sometimes  added  to  the  alloy  in  the 
form  of  copper-phosphide,  which  is  made  by  reducing  acid 
phosphate  with  charcoal.  This  is  added  to  the  extent  of 
from  one  and  a  half  to  three  and  a  half  per  cent.  Dry  phos- 
phorus may  be  added  in  the  crucible  if  preferred  to  phos- 
phor-tin or  copper-phosphide. 

Phosphor-bronze  was  early  known  to  chemists,  but  its 
valuable  qualities  as  a  material  to  be  used  in  construction 
were  first  made  known  by  MM.  Montefiori,  Levi,  and  Kun- 
zel,  who  discovered  the  alloy  in  the  year  1871.  According  to 
Dick,*  who  introduced  the  alloy  into  the  United  States,  the 
chemical  action  of  phosphorus  on  the  metals  composing  the 
alloy  is  two-fold  :  it  reduces  any  oxides  dissolved  therein, 
and  it  forms  with  the  purified  metals  a  homogeneous  and 
regular  alloy,  the  hardness  and  the  toughness  of  which  are 
completely  under  control. 

We  summarize,  from  the  same  source,  the  special  uses  of 
phosphor-bronze  :  I.  It  is  very  tough,  and  thus  fitted  for  pis- 
ton rings  and  valve  covers.  2.  It  is  very  tough  and  hard,  and 
therefore  used  for  machine  castings,  pinions,  cog-wheels,  pro- 
peller screws,  hydraulic  press  and  pump  barrels,  piston  rods, 
screw  bolts  for  steam  cylinders,  and  hardware.  3.  Very  hard 
bronze  is  adopted  for  bearings  of  heated  rolls,  valves,  etc. 
4.  Harder  and  stronger  alloys  than  ordinary  bell  metal  are 
employed  for  bells,  steam -whistles,  etc.  5.  Acquiring  great 
toughness,  elasticity,  and  strength  under  the  hammer,  it  is 


Journal  Franklin  Institute,  1878. 


BRONZES  AND  OTHER  COPPER-TIN  ALLOYS.  145 

used  for  hammered  piston-rods  and  bolts.  6.  As  bearing 
metal  it  is  said  to  be  better  than  the  best  gun-metal,  very 
much  less  liable  to  heat  than  gun-metal,  and  when  heated,  it 
does  not  cut  the  journal. 

Ordnance  has  been  made  of  this  modification  of  gun- 
bronze  by  European  nations,  and  has  been  found  to  excel  in 
strength,  toughness,  and  endurance.  Small  arms  have  also 
been  made  of  it,  and,  in  ship-work,  the  screws  and  sometimes 
rods  in  small  vessels.  When  sheathing  of  this  metal  is  used, 
it  is  found  to  possess  exceptional  power  of  resisting  corro- 
sion. 

82.  Uses  of  Phosphor-Bronze. — The  comparatively  high 
cost  of  phosphor-bronze  has  checked  its  introduction,  not- 
withstanding its  undeniable  excellence.  It  is  said  to  be 
stable,  not  losing  much  phosphorus  by  remelting,  the  tempera- 
ture of  the  fusion  of  the  alloy  being  kept  low,  ranging  from 
752°  to  932°  Fahr.  (400°  to  500°  C). 

Phosphor-tin  is  now  sold  in  the  market  for  use  in  making 
this  bronze  ;  it  is  known  by  its  number,  as  No.  o,  No.  I. 

All  alloys  made  with  copper  and  phosphor-tin  may  be 
forged  cold,  provided  the  percentage  of  tin  does  not  much 
exceed  12  per  cent.,  and  by  this  treatment  they  increase  con- 
siderably in  hardness.  An  alloy  of  94  or  95  per  cent,  of  cop- 
per, and  6  or  5  per  cent,  of  phosphor-tin,  may  attain  the  hard- 
ness of  ordnance  steel,  while  the  toughness  of  the  bronze 
remains  high.  When  expense  does  not  permit  the  use  of 
phosphor-bronze  instead  of  ordinary  bronze,  the  quality  of 
the  latter  may  be  very  materially  improved  by  re-placing 
one-tenth  of  the  percentage  of  tin  by  phosphor-tin,  which 
carries  enough  phosphorus  into  the  bronze  to  deoxidize  the 
metals  in  the  alloy,  and  the  small  increase  in  cost  is  coun- 
terbalanced by  soundness  of  castings  and  improved  working. 

It  is  best  to  avoid  the  use  of  zinc  in  making  phosphor- 
bronze  with  phosphor-tin.  Take,  for  heavy  main-shaft  jour- 
nals, 85  per  cent,  of  copper  and  15  per  cent,  of  phosphor-tin, 
and  for  coupling  and  crank-rod  journals,  90  per  cent,  of  cop- 
per and  10  per  cent,  of  phosphor-tin  ;  these  alloys  have  great 
hardness  and  high  tensile  strength  and  toughness. 
10 


146  MATERIALS  OF  ENGINEERING—NON-FERROUS  METALS. 

As  a  substitute  for  ordinary  bronze  take  : 

,  (35  parts  of  zinc, 

30  parts  of  ^ood  brass  \  ~,  . 

(  65  parts  of  copper, 

16  parts  of  copper, 
4  parts  of  phosphor-tin,  No.  O. 

Gearing,  tuyeres  for  blast-furnaces,  and  wire  ropes  of  this 
alloy  have  been  successfully  used,  the  latter  on  the  hoists  of 
deep  mines  in  Europe  ;  they  have  the  advantages  of  great 
strength  and  freedom  from  corrosion. 

Phosphide  of  copper  may  be  used  in  the  manufacture  of 
phosphor-bronze.  It  may  be  prepared  by  adding  phosphorus 
to  copper  sulphide  solution  and  boiling,  adding  sulphur  as 
the  sulphide  is  precipitated.  The  precipitate  is  carefully 
dried,  melted,  and  cast  into  ingots.  When  of  good  quality 
and  in  proper  condition,  it  is  quite  black. 

Phosphide  of  tin  is  oftener  employed.  When  the  precipi- 
tated tin  obtained  by  the  addition  of  zinc  to  a  solution  of 
chloride  of  tin  (SnCl2)  is  heated  with  phosphorus  in  the  pro- 
portions of  about  nine  atoms  of  tin  to  one  of  phosphorus,  the 
phosphide  (SngP)  is  produced.  This  compound  resembles 
cast  zinc,  is  crystalline,  melts  at  about  370°  C.  (700°  F.)  and 
can  be  easily  introduced  into  the  crucible  in  the  process  of 
manufacture  of  bronze. 

"  Phosphor-bronze  "  is,  therefore,  any  copper-tin  alloy  or 
bronze  which  has  been  fluxed,  in  the  process  of  making  the 
alloy,  by  the  addition  of  a  measurable  quantity  of  phosphorus. 
The  metalloid  maybe  added  either  pure  or  combined,  and 
either  to  the  alloy  itself  or  to  one  of  its  constituents,  usually 
to  the  tin — often  as  phosphate  of  copper,  before  mixing.  A 
small  quantity  of  phosphorus,  chemically  uniting  with  copper, 
hardens  and  strengthens  it.  Added  in  the  process  of  manu- 
facture, in  larger  amount,  it  prevents  the  formation  of  copper, 
or  other  metal,  oxide,  and  thus  produces  an  alloy  of  such  purity 
as  to  give  greatly  increased  strength,  and  ductility  as  well, 
and  also  greater  homogeneousness. 

In  using  phosphate  of  copper,  Messrs.  Ruoltz  and  de  Fon- 
tenay  mix  the  sirupy  acid  phosphate  with  0.20  charcoal  and 


BRONZES  AND  OTHER  COPPER-TIN  ALLOYS.  147 

melt  in  plumbago  crucibles,  and  use  this  material  in  the  fol- 
lowing proportions,*  the  phosphate  containing  9  per  cent, 
phosphorus : 

In  preparing  phosphor-bronze  it  seems  immaterial  whether 
phosphor-copper  or  phosphor-tin  is  used,  though  the  former 
is  more  likely  to  find  an  extended  use,  as  it  is  applicable,  not 
only  for  phosphor-bronze,  but  for  other  copper  alloys  contain- 
ing no  tin,  as  yellow  brass,  German  silver,  etc.,  and  for  pure 
copper.  It  also  possesses  the  advantage  of  being  able  to 
take  up  the  greatest  quantity  of  phosphorus,  and  consequently 
to  offer  the  efficient  reagent  in  the  most  compact  form. 

In  making  phosphor-bronze  or  copper  alloys  of  all  sorts, 
the  copper  should  first  be  melted  in  the  usual  way,  with  a 
cover  of  charcoal  put  over  it  as  quickly  as  possible.  After 
the  required  quantities  of  tin,  zinc,  etc.,  have  been  added, 
or  in  case  of  gun  metal  or  brass  scrap,  after  the  latter  has 
been  completely  melted,  the  small  exactly  weighed  quantity 
of  phosphor-copper  is  added  while  the  metal  is  continually 
stirred.  For  stirring,  a  graphite  bar,  a  strip  cut  from  an  old 
plumbago  crucible,  or  a  bar  of  retort  carbon  should  be  used. 
The  stirring  has  to  be  done  carefully,  and  the  metal  then 
freed  of  the  coal  and  scoriae  floating  on  the  top  ;  it  should  be 
poured  before  the  surface  begins  to  be  covered  with  a  skin. 
The  latter  point  and  the  careful  stirring  cannot  be  too 
urgently  recommended.  Phosphor-metals  should  always  be 
covered  with  charcoal  when  remelted.  A  further  addition  of 
an  extremely  small  quantity  of  phosphor-copper  is  necessary 
only  in  case  the  metal  should  not  assume  a  bright  mirror 
face. 

For  preparing  phosphor-bronze  or  remelting  old  gun  metal 
and  turnings,  the  addition  of  i^  Ib.  to  i^  Ib.  of  phosphor- 
copper  of  15  per  cent,  phosphorus  is  generally  sufficient  fora 
hundred-weight  of  metal.  In  making  or  remelting  brass, 
an  addition  of  J^  to  ^  part  only  is  required  per  hundred. 
A  larger  percentage  increases  the  hardness,  but  may  lead 
to  brittleness.  The  phosphor-copper  of  15  per  cent,  phos- 
phorus itself  is  so  brittle  that  the  small  ingots  of  about  2  Ib. 

*  Lebasteur,  p.  321. 


148  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

(I  kg.)  weight  in  which  it  is  usually  sold,  can  be  broken  in  the 
hand  by  a  light  blow  with  a  hammer  into  such  pieces  as  are 
required. 

Sheathing  metal  made  of  phosphor-bronze  is  found  to 
resist  the  action  of  sea-water  remarkably  well.  In  experi- 
ments made  at  Blankenbergh,  lasting  six  months,  comparing 
the  best  English  copper  and  phosphor-bronze,  the  following 
results  were  arrived  at :  * 


LOSS    OF 

THICKNESS  OF  THE  SHEETS 

WEIGHT       BE-         WEIGHT        1                 WEIGHT. 

—  0.236  in. 

FORE    IMMER-      AFTFR    TM_ 

=  0.6  cm. 

SION. 

MERSION. 

Actual. 

Per 
cent. 

Sheet  of  copper 

7d.  A. 

72  2 

2  2 

3     QTC 

Do.              

88  Q 

86  2 

27 

•3    TOO 

Sheet  of  phosphor-bronze  .... 

695 

68.75 

0.75 

I.I23 

Do.              Do  

II4-3 

112.97 

i-33 

I.I95 

The  loss  in  weight,  therefore,  due  to  the  oxidizing  action 
of  sea-water  during  the  six  months'  trial,  averaged  for  the 
English  "copper  3.058  per  cent.,  while  that  of  the  phosphor- 
bronze  was  but  1.158  per  cent. 

According  to  Delalot,f  true  phosphor-bronze  is  not  an 
alloy;  it  is  a  combination  of  copper  with  phosphorus;  it  is 
simply  a  phosphide  of  copper  in  definite  proportions.  The 
metal  unites  with  the  metalloid  either  cold  or  hot ;  for  some 
applications  of  phosphor-bronze  the  cold  method  suffices. 
Phosphor-bronze  made  by  the  hot  process  does  not  allow  the 
introduction  of  simple  bodies  other  than  the  metal  and  the 
metalloid.  Copper  exempt  from  arsenic,  antimony,  iron,  or 
zinc,  is  required  ;  it  must  be  commercially  pure.  The  manu- 
facturer may  choose  from  three  kinds  of  phosphorus,  ordinary, 
amorphous,  and  all  the  earthy  biphosphates.  Amorphous 
phosphorus  is  the  most  expensive,  but  the  best.  The  secret 
of  making  good  phosphor-bronze  lies  in  the  working  of  .the 


*  M.  J.  Maure,  Engineering,   Sect.  T2  ;  1873. 
f  Moniteur  Industrielle  Beige  ;  1878.  v 


BRONZES  AND  OTHER  COPPER-TIN  ALLOYS.  149 

furnace  and  in  practice.  The  following  are  the  best  combina- 
tions in  definite  proportions.  The  minimum  and  maximum 
percentages  of  phosphorus  in  phosphor-bronze  are  2  and  4. 
Five  sorts  of  phosphor-bronze,  however,  are  considered  to 
answer  all  requirements. 

0.  Ordinary  phosphor-bronze  of  2  per  cent,  of  phosphorus. 

1.  Good  "  "       "  2% 

These  two  numbers  are  superior  to  ordinary  bronze  and 
steel  in  all  cases. 

2.  Superior  phosphor-bronze  of  3  per  cent,  of  phosphorus. 

3.  Extra  "  "        "  3j£ 

4.  Maximum      "  "        "  4  " 

These  three,  according  to  Delalot,  are  superior  to  any 
other  bronzes.  Above  No.  4,  phosphor-bronze  is  useless ; 
below  o,  it  is  inferior  to  common  bronze  and  steel.  The 
price  of  phosphor-bronze  unworked,  for  all  numbers,  should 
not  exceed  that  of  copper  by  over  ten  per  cent.  Nos.  3  and  4 
are  comparatively  unoxidizable. 

It  is  stated  by  Dumas  that  the  characteristics  of  these  alloys 
change  with  the  addition  of  phosphorus.  The  color,  when 
the  proportion  of  phosphorus  exceeds  ^  per  cent,  becomes 
warmer,  and  like  that  of  gold  largely  alloyed  with  copper. 
The  grain  and  fracture  approximate  to  those  of  steel.  The 
elasticity  is  considerably  increased,  the  tenacity  also  becomes 
in  some  cases  more  than  doubled ;  the  density  is  also  in- 
creased, and  to  such  a  degree  that  some  phosphor-bronzes 
are  with  difficulty  touched  by  the  file.  The  metal,  when 
cast,  has  great  fluidity,  and  fills  the  mo'uld  perfectly,  exhibit- 
ing the  smallest  details.  By  varying  the  doses  of  phosphorus 
and  tin,  the  particular  characteristic  of  the  alloy  which  is 
most  desired  can  be  varied  at  pleasure. 

83.  Tabular  Exhibit  of  Properties  of  the  Copper-Tin 
Alloys.* — The  following  table  is  a  list  of  about  140  different 
alloys  of  copper  and  tin,  giving  some  of  their  mechanical  and 

physical  properties. 

. ^ __ 

*  Prepared  originally  for  the  U.  S.  Board  ;  Committee  on  Alloys'  Report, 
vol.  i.,  1878,  p.  389. 


ISO  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


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154  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


PROPERTIES  OF  ALLOYS  OF  COPPER  AND  TIN. 

Remarks. 

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BRONZES  AND  OTHER  COPPER-TIN  ALLOYS. 


155 


m  t^co  O^OO   00000 
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OF  THE 


MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS. 

In  the  above  table  the  figures  or  order  of  ductility,  malle- 
ability, hardness,  and  fusibility  are  taken  from  Mallet's  experi- 
ments on  a  series  of  sixteen  alloys,  the  figure  I  representing 
the  maximum  and  16  the  minimum  of  the  property.  The 
ductility  of  the  brittle  metals  is  represented  by  Mallet  as  o. 

The  relative  ductility  given  in  the  table  of  the  alloys  ex- 
perimented on  by  the  U.  S.  Board,  is  the  proportionate  exten- 
sion of  the  exterior  fibres  of  the  pieces  tested  by  torsion  as 
determined  by  the  autographic  strain-diagrams.  It  will  be 
seen  that  the  order  of  ductility  differs  widely  from  that  given 
by  Mallet. 

The  figures  of  relative  hardness,  on  the  authority  of  Cal- 
vert  and  Johnson,  are  those  obtained  by  them  by  means  of  an 
indenting  tool.  The  figures  are  on  a  scale  in  which  cast  iron 
is  rated  at  1,000.  The  word  "broke"  in  this  column  indi- 
cates the  fact  that  the  alloy  opposite  which  it  occurs  broke 
under  the  indenting  tool,  showing  that  the  relative  hardness 
could  not  be  measured,  but  was  considerably  greater  than 
that  of  cast  iron.  The  quality  of  the  iron  is  not  specified. 

The  figures  of  specific  gravity  show  a  fair  agreement 
among  the  several  authorities  for  the  alloys  containing  more 
than  35  per  cent,  of  tin,  except  those  given  by  Mallet,  which 
are  in  general  very  much  lower  than  those  by  all  the  other 
authorities.  In  the  alloys  containing  less  than  35  per  cent, 
of  tin  there  is  a  wide  variation  among  all  the  different  authori- 
ties ;  Mallet's  figures,  however,  being  generally  lower  than  the 
others.  Several  of  the  figures  of  specific  gravity  have  been 
selected  from  Riche's  results  of  experiments  on  the  effects  of 
annealing,  tempering,  and  compression,  which  show  that  the 
latter  especially  tends  to  increase  the  specific  gravity  of  all 
the  alloys  containing  less  than  20  per  cent,  tin  to  about  8.92. 
This  result,  as  stated  in  the  discussion  on  specific  gravity 
above,  is  due  merely  to  the  closing  up  of  the  blow-holes, 
and  thus  diminishing  the  porosity.  The  specific  gravity  of 
8.953  was  obtained  by  Major  Wade  by  casting  a  small  bar  in 
a  cold  iron  mould  from  the  same  metal  which  gave  a  specific 
gravity  of  only  8.313  when  cast  in  the  form  of  a  small  bar  in  a 
clay  mould.  The  former  result  is  exceptionally  high,  and  in- 


BRONZES  AND  OTHER  COPPER-TIN  ALLOYS.  Itf 

dicates  the  probability  that  every  circumstance  of  the  melt- 
ing, pouring,  casting,  and  cooling  was  favorable  to  the  ex- 
clusion of  the  gas  which  forms  blow-holes,  and  to  the  forma- 
tion of  a  perfectly  compact  metal. 

The  figures  of  tenacity  given  by  Mallet,  Muschenbroek, 
and  Wade  agree  with  those  found  in  the  experiments  de- 
scribed in  this  volume  as  closely  as  could  be  expected  from 
the  very  variable  strengths  of  alloys  of  the  same  composition 
which  have  been  found  by  all  experimenters. 

Mallet's  figure  for  copper,  24.6  tons,  or  55,104  pounds,  is 
probably  much  too  high  for  cast  copper;  the  piece  which  he 
tested  was  probably  rolled  or  perhaps  drawn  into  wire.  Has- 
w ell's  Pocket  Book  gives  the  following  as  the  tensile  strength 
of  copper ;  the  names  of  the  authorities  are  not  given  : 

Pounds  per 
square  inch. 

Copper,  wrought 34>ooo 

Copper,  rolled 36,000 

Copper,  cast  (American) 24,250 

Copper,  wire 61,200 

Copper,  bolt 36,800 

This  table  of  comparison  of  authorities  is  by  no  means 
complete.  No  account  is  taken  of  a  vast  number  of  ancient 
bronzes,  weapons,  medals,  coins,  and  sonorous  instruments 
which  have  been  described  by  various  writers.  These,  how- 
ever, differ  but  little  in  composition  and  properties  from  the 
ordnance  and  bell  metal  given  in  the  tables. 

It  will  be  observed  that  while  there  is  considerable  irregu- 
larity in  the  tenacity  of  the  alloys  containing  more  than  27.5 
per  cent,  of  tin,  they  are  all  extremely  weak,  the  highest 
strength  found  by  any  experimenter  being  only  8,736  pounds, 
and  valueless  for  all  purposes  in  which  strength  is  required. 

It  has  been  shown  that  the  useful  alloys,  those  which  con- 
tain less  than  27.5  per  cent,  of  tin,  have  strengths  which  are 
nearly  proportional  to  their  densities. 


CHAPTER  V. 

THE   BRASSES  AND   OTHER    COPPER-ZINC   ALLOYS. 

84.  Brass  is  a  term  which  is  applied  by  many,  and  espe- 
cially older,  authors  indifferently  to  all  alloys  composed  princi- 
pally of  copper,  combined  with  either  tin  or  zinc.     The  alloy 
of  copper  and  tin  and  its  minor  modifications  are  now  becom- 
ing better  known  as  bronze,  and  the  name  brass  is  generally 
restricted    to    the    designation    of   alloys    consisting    mainly 
of  copper    and    zinc.     "  Brass "  ordnance   is   properly  called 
bronze  ordnance,  and  the  compositions  used  in  the  bearings  of 
machinery,  which   are   usually  of  somewhat   similar  compo- 
sition, are  also  properly  called  bronzes.     The  alloys  of  copper, 
tin  and  zinc,  which  occupy   intermediate  positions  between 
the  bronzes  and  the  brasses,  are  as  often  known  by  the  one 
name  as  by  the  other. 

85.  Copper  and  Zinc  together  form  "  Brass,"  which  is  usu- 
ally made  nearly  in  the  proportion,  copper,  66^3,  zinc  33/^« 
Brasses  of  certain  other  proportions  have  specific  names,  as 
Tourbac,  Pinchbeck.     The  mixture  and  fusion  of  the  metals 
must  be  so  conducted  that  the  loss  of  zinc  by  volatilization 
may  be  the  least  possible ;  there  is  always  some  loss,  and  it 
may  not  only  be  serious  as  a  matter  of  cost,  but  the  introduc- 
tion of  oxides  into  the   alloy  is   exceedingly  injurious  to  its 
quality.    The  fusion  is  generally  performed  in  crucibles  heated 
in  air-furnaces. 

The  change  of  color  and  of  other  qualities  with  the  intro- 
duction of  zinc  is  gradual  and  very  similar  in  character  to 
that  produced  by  the  admixture  of  tin  ;  but  the  quantity  of 
zinc  demanded  to  produce  the  same  modification  is  about 
twice  as  much  as  of  tin.  On  adding  zinc,  the  deep  red  color 
of  copper  is  changed  at  once,  becoming  lighter  and  lighter, 


BRASSES  AND  OTHER  COPPER-ZINC  ALLOYS. 


159 


and  finally  shading  into  a  grayish  white  and  then  assuming 
more  of  the  color  of  zinc.  The  alloy  generally  increases  in 
hardness  and  loses  ductility  as  the  percentage  of  zinc  is  in- 
creased, up  to  a  maximum,  which  being  passed,  ductility 
increases  again.  The  most  ductile  are,  however,  those  which 
contain  70  to  85  per  cent,  copper,  30  to  15  of  zinc,  the  first 
being  called  "tombac,"  the  latter  "brass." 

86.  Mallet's  Classification.— The   following  is   Mallet's 
table  of  the  copper-zinc  alloys : 

TABLE   XXI. 

PROPERTIES   OF   COPPER-ZINC    ALLOYS. 


ORDI 

IR  OF 

AT-    COM  P. 

COPPKR 

S.  G. 

COLOR* 

FRACT. 

TENACITY. 

Mall. 

Hard. 

Fus. 

by  anal. 

Cu  Zn 

i 

per  ct. 

IOO. 

8.667 

red 

Tons  per  sq.  in. 
24.6 

g 

22 

10 

98.80 

8.605 

red  -yellow 

coarse 

12.1 

6 

21 

J5 
J4 

9 

90.72 

8.607 

vi 

fine 

"•5 

4 

20 

13 

8 

88.60 

8.633 

it 

u 

12.8 

2 

19 

12 

I 

87.30 

85.40 

*S9« 

yellow-red 

ii 

fine  fibre 

13-2 
n.  i 

0 

5 

18 
17 

ii 

IO 

5 

83.02 

8.4J5 

" 

13-7 

IT 

16 

4 
3 

79-65 
74-58 

8.448 
8-397 

pale  yellow 

14.7 
i3-i 

7 

10 

15 
14 

7 

a 

66.18 

8.299 

deep     ' 

12.5 

3 

23 

6 

i 

49-47 

8.230 

"       " 

coarse 

9.2 

12 

12 

6 

i 

32-85 

8.263 

dark      " 

19-3 

I 

10 

6 

!    i 

31-52 
30-36 

7.721 
7.836 

silver  white 
silver  white 

2.1 
2.2 

very  brittle 

I 

5 
5 

!    2 

29.17 
28.12 

7.019 

light  gray 
ash       ' 

vitreous 

0.7 
3-2 

brittle 

7 

3 

5 
5 

8          21 
8          22 

27.10 
26.24 

7.'882 

light  ; 

coarse 

0.9 

0.8 

u 

9 

i 

5 
5 

8       23 

25-39 

7-443 

ash      ' 

fine 

5-9 

slight  duct. 

i 

5 

1       3 

24.50 

7-449 

it                * 

** 

3.i 

brittle 

2 

4 

*       4 

19.65 

7-371 

44 

1.9 

4 

3 

i       5 

O          I 

16.36 

O. 

6.605 
6  801; 

dark    ' 

1.8 
15.2 

ii 

27 

2 
I 

u*°Vj 

J 

In  the  above  table,  the  minimum  of  hardness  and  fusibility  is  denoted  by  i. 

The  conclusion  of  Storer*  that  these  alloys  are  mixtures 
rather  than  true  compounds,  is  accepted  by  Watts  and  other 
authorities. 

87.  Uses  of  Brass. — Brass  is  the  alloy  commonly  em- 
ployed in  the  arts  in  the  construction  of  scientific  apparatus, 


*  Mem.  Am.  Acad.,  N.  S.,  vol.  viii,  p.  97. 


l6o  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

mathematical  instruments,  and  small  parts  of  machinery.  It 
is  cast  into  parts  of  irregular  shape,  drawn  into  wire,  or  rolled 
into  rods  and  sheets.  It  is  harder  than  copper,  very  malle- 
able and  ductile,  and  can  be  "  struck  up  "  in  dies,  formed  in 
moulds,  or  "  spun  "  into  vessels  of  a  wide  variety  of  forms  if 
handled  cold  or  slightly  warm  ;  it  is  brittle  at  a  high  tempera- 
ture. A  common  proportion  for  making  brass  is  copper  66, 
zinc  34.  This  alloy  is  a  much  slower  conductor  of  electricity 
and  of  heat  than  copper,  is  more  fusible,  oxidizes  very  slowly 
at  low  temperatures,  but  rapidly  at  a  high  heat. 

The  brass  of  Romilly,  which  works  remarkably  well  under 
the  hammer,  is  composed  of  copper  70,  zinc  30 ;  English 
brass  is  often  given  33  per  cent,  zinc,  and  for  rolled  brass  40 
per  cent.  This  constitutes  "  Muntz  sheathing  metal,"  as 
patented  by  G.  F.  Muntz  in  1832.  The  proportion  of  zinc 
ranges,  however,  for  such  purposes,  from  37  to  50  per  cent, 
copper  63  to  50* 

88.  Muntz  Metal  is  thus  described  by  its  inventor  : — 
"  I  take  that  quality  of  copper  known  in  the  trade  by  the  ap- 
pellation of  *  best  selected  copper,'  and  that  quality  of  zinc, 
known  in  England  as  '  foreign  zinc/  and  melt  them  together 
in  the  usual  manner  in  any  proportion  between  50  per  cent, 
of  copper  to  50  per  cent,  of  zinc,  and  63  per  cent,  of  copper 
to  37  per  cent,  of  zinc,  both  of  which  extremes,  and  all 
intermediate  proportions,  will  roll  and  work  at  a  red  heat  ; 
but  as  too  large  a  proportion  of  copper  increases  the  diffi- 
culty of  working  the  metal,  and  too  large  a  proportion  of 
zinc  renders  the  metal  too  hard  when  cold,  I  prefer  the 
alloy  to  consist  of  about  60  per  cent,  of  copper  to  40  per 
cent,  of  zinc.  This  compound  I  cast  into  ingots  of  any  con- 
venient weight,  and  then  heat  them  to  a  red  heat,  and  roll  or 
work  them  while  at  that  heat  into  bolts  and  other  like  ship's 
fastenings,  in  the  same  manner  as  copper  is  rolled  or  worked, 
but  only  taking  care  not  to  overheat  the  metal  so  as  to  pro- 
duce fusion,  and  not  to  put  it  through  the  rolls  or  work  it 
after  the  heat  has  left  it  too  much,  say,  when  the  red  heat 
goes  off." 

This  alloy  is  cast  into  ingots,  and  rolled,  hot,  into  sheets, 


BRA SSES  A ND  O  THER  COPPER-ZINC  ALLO  YS.  1 6 1 

which  are  cleaned  by  pickling  and  washed  before  they  are 
sent  into  the  market.  As  this  alloy  is  cheaper  and  more  du- 
rable than  copper  sheathing,  and  equally  effective,  it  has  dis- 
placed the  latter  almost  entirely  in  the  protection  of  wooden 
ships.  When  made  on  a  large  scale,  the  alloy  is  melted  in  a 
reverberatory  furnace. 

89.  Special  Properties. — Farmer  has  deposited  brass  by 
electrolysis  and  obtained  an  alloy  containing  copper  75,  zinc 
25,  as  ductile  and  malleable  as  rolled  brass. 

The  brasses,  or  copper-zinc  alloys,  although  probably  of 
more  extended  use  than  the  bronzes  or  copper-tin  alloys,  are 
not  as  well  studied  as  the  latter. 

The  metals,  as  already  stated  (§  85),  mix  in  all  propor- 
tions, and  produce  alloys  of  which  the  general  character  has 
been  shown  in  the  introductory  chapter  of  this  part  of  the 
work  and  in  the  earlier  paragraphs  of  this  chapter. 

The  red  color  of  copper,  in  this  series,  fades  into  yellow 
very  gradually,  and  becomes  golden-yellow  at  about  40  per 
cent,  zinc  ;  the  color  then  becomes  lighter,  and  at  60  per 
cent,  zinc  is  bluish-white  or  silvery.  With  the  change  of 
color  occurs  the  same  change  of  strength  and  ductility  noted 
with  the  copper-tin  alloys,  but  it  requires  about  twice  as 
much  zinc  as  tin  to  produce  it.  The  white  metals  richest  in 
copper  are,  like  those  of  the  bronze  class,  too  brittle  to  be  of 
use  in  engineering  construction,  but  the  yellow  metals  ob- 
tained with  from  40  to  50  per  cent,  zinc  are  very  valuable. 

Brass  has  a  high  coefficient  of  expansion,  0.000054  to 
0.000056  per  Cent,  degree  (0.00003  to  0.000033  per  degree 
F.).*  Yellow  brass  fuses  at  from  1,870°  F.  (1,021°  C),  and 
other  compositions  from  1,000°  F.  (550°  C.,  nearly)  to  2,000°  F. 
(1,100°  C,  nearly),  and  loses  strength  and  ductility  as  its  tem- 
perature rises.  The  composition  of  the  several  most  useful 
brasses  is  given  elsewhere.  Brass  for  fine  work  is  often  made 
of  copper,  80;  zinc,  17;  tin,  3  ;  "fine  brass"  of  2  copper,  I 
of  zinc  ;  sheet  brass  of  3  copper,  I  zinc.  A  hard  solder  is 
made  of  3  parts  brass  to  I  of  zinc,  etc.,  etc.  Castings  shrink 
in  cooling  T\  inch  to  the  foot  (0.015). 

*  Vide  Chapter  I. 
II 


1 62  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Hydrochloric  acid  reddens  brass  by  dissolving  its  zinc; 
ammonia  whitens  it  by  taking  up  the  copper. 

Brass  may  be  made  tough  and  soft,  hard  and  brittle,  strong 
or  weak,  elastic  or  inelastic,  dull  of  surface  or  lustrous  as 
a  mirror,  friable  or  nearly  as  malleable  and  ductile  as  lead,  as 
may  be  desired,  by  varying  its  composition.  No  known  ma- 
terial, perhaps  not  even  excepting  iron,  can  be  given  so  wide 
a  range  of  quality  or  so  wonderful  a  variety  of  uses.  All  the 
common  varieties  are  composed  of  67  to  70  parts  copper  and 
33  to  30  of  zinc.  A  little  lead  is  often  added  to  soften  and 
cheapen  it  and  tin  in  small  proportion  to  strengthen  it. 

Brass  is  subject  to  flow  under  stress,  like  all  other  metals 
of  what  the  Author  has  called  the  "  tin  class,"  and  it  is  not 
safe  to  leave  heavy  loads  upon  it.  Weights  should  not  usually 
be  hung  upon  brass  chains,  or  upon  brass  tie-rods.  The  alloy 
is  capable  of  being  considerably  hardened  by  compression,  as 
when  rolled  into  sheets,  or  by  wire-drawing,  and  becomes 
much  stronger  and  is  less  liable  to  permanent  change  under 
load.  Some  compositions  are  very  elastic  and  make  good 
springs  for  intermittent  and  occasional  use. 

The  thin  sheet  brass  used  for  metallic  cartridges  and 
other  purposes  requiring  a  metal  in  this  form  of  great  strength 
combined  with  ductility,  is  subject,  frequently,  to  a  singular 
deterioration  with  age  which  seem  to  be  partly  a  physical  and 
partly  a  chemical  change.  It  results,  sometimes  in  a  very 
brief  interval,  in  the  entire  destruction  of  the  essential  proper- 
ties of  such  forms  of  this  alloy.  This  has  been  studied  by 
Egleston,  but  the  results  of  irvestigation  are  not  yet  fully 
known. 

Weems  has  found  '*  that  a  pressure  of  4,000  tons  (or  ton- 
nes) being  applied  to  brass,  in  the  endeavor  to  produce  brass 
tubes  by  "  squirting  "  as  is  usual  with  lead,  causes  a  separa- 
tion of  the  zinc,  which  issues  as  a  zinc  pipe,  leaving  the  cop- 
per behind.  This  is  considered  a  proof  that  this  alloy  is  a 
mixture  rather  than  a  chemical  compound. 

90.  Applications  in  the  Arts. — Bronze  and  brass  have  in- 
numerable uses  in  the  arts  :  locks,  keys,  shields,  escutcheons, 

*  Land.  Engineer,  1883. 


BRASSES  AND  OTHER  COPPER-ZINC  ALLOTS.  163 

hinges,  journal-bearings,  pump-plungers,  screw  propellers,  all 
small  parts  of  machinery,  optical  and  other  philosophical 
instruments,  cabinet-makers'  fittings,  sheathing  of  ships.  Even 
so-called  copper  castings  usually  contain  a  small  amount  of 
zinc — 2  to  5  per  cent.,  to  give  them  soundness. 

The  copper  and  brass  manufactures  of  the  United  States 
are  very  extensive  and  of  excellent  character,  both  as  to  ma- 
terial and  workmanship,  and  in  those  departments  which  are 
purely  mechanical,  are  probably  unequalled  elsewhere.  The 
purest  copper  is  at  their  doors  and  the  best  of  zinc ;  while 
tin  is  likely,  in  time,  to  be  largely  produced  in  this  country 
also. 

Brass  to  be  used  in  the  rolling  mill  in  the  manufacture  of 
sheet  metal,  is  cast  between  marble  blocks  which  are  separ- 
ated to  a  distance  which  determines  the  thickness  of  the 
ingot  or  slab.  The  marble  is  coated  with  a  thin  layer  of 
loam  prepared  for  the  purpose;  the  sides  are  closed  with 
moulding  sand.  The  slabs,  when  cast,  are  rolled,  several 
"  passes"  being  necessary,  and  the  sheets  are  annealed  at 
intervals,  and  when  finally  finished  are  "  pickled  "  to  give  them 
a  good  surface.  For  fine  work,  the  surfaces  must  sometimes 
be  repeatedly  scraped  during  the  process  of  rolling  to  remove 
surface  impurities  and  defects. 

Wire  brass  is  similarly  treated,  and  the  plates  are  then  slit 
into  rods  in  the  "  slitting  mill,"  rolled  to  give  them  a  section 
which  can  be  handled  in  the  wire-mill,  and  the  rods  are  then 
drawn  as  in  making  iron  wire.* 

Brass  tubes  for  steam  boilers,  condensers  and  other  pur- 
poses, are  usually  drawn,  as  are  many  other  forms  of  section. 

91.  Working  Brass. — Yellow  brass,  and  several  composi- 
tions of  similar  character,  are  so  easily  worked  cold  that 
many  articles  are  made  by  "striking  up"  in  a  die,  under  a 
press  or  a  drop-hammer.  Where  a  considerable  change  of 
form  is  necessary,  the  work  is  done  by  a  succession  of  opera- 
tions alternating  with  annealing.  Rolls  may  often  be  used  to 
form  brass  into  the  desired  shape  and  they  are  still  oftener 
employed  to  impress  a  pattern  on  the  sheet. 

*  Part  I,  §  138,  p.  196. 


164  MATERIALS  CF  ENGINEERING— NON-FERROUS  METALS. 

"  Spinning  "  is  a  peculiar  and  very  interesting,  as  well  as 
useful  process.  It  is  employed  in  altering  the  shape  of  a 
disk  or  of  a  cylinder  which  can  be  "  chucked  "  and  held  in  a 
lathe,  while  the  tool  of  the  workman,  pressing  on  the  edge, 
turns  it  over  and  forces  it  into  a  new  shape. 

Spinning  brass  often  consists  merely  in  forming  a  flat  sheet, 
turning  in  the  lathe,  by  the  pressure  of  a  smooth  burnishing 
tool.  Chasing  is  done  with  a  graver,  and  matting  and  emboss- 
ing with  formers  and  hammers.  In  burnishing  to  give  high 
lustre,  the  metal  is  kept  wet  with  sour  beer,  while  the  burnisher 
by  a  steady  friction  produces  the  polish. 

"  Burnishing  "  consists  in  giving  a  fine  lustrous  surface  by 
the  pressure  and  friction  of  a  smooth,  highly  polished  steel 
tool,  lubricated  well,  as  above.  The  surface  is  first  prepared 
by  giving  it  a  good  polish  by  the  usual  methods.  The 
"burnishers"  are  made  of  fine  steel,  carefully  polished  with 
crocus  and  oil,  and  kept  in  the  most  perfect  possible  con- 
dition. 

The  working  of  brass  in  the  lathe  requires  especial  care, 
not  only  in  the  handling,  but  also  in  the  form  of  the  tool. 
The  cutting  edge  is  given  a  much  larger  angle  than  in  cutting 
iron  and  steel ;  hand-tools  require  to  be  given  precisely  the 
right  inclination  and  a  constant  rotation  ;  the  velocity  of 
cutting  greatly  exceeds  that  usual  with  iron. 

Brass  tubes  are  sometimes  made  by  simply  rolling  sheet- 
brass,  cut  to  exact  size,  upon  a  mandrel  and  brazing  or  solder- 
ing the  joint ;  but  they  are  more  usually  "  drawn." 

The  roll  and  its  mandrel  are  sent  through  the  draw-plate 
together  and  the  tube  is  thus  drawn  to  size  and  the  soldered 
lap  becomes  distinguishable  only  by  the  color  of  the  joint. 

Locomotive  tubes,  and  others  required  to  bear  very  high 
temperatures  and  pressures,  are  drawn  solid  and  seamless. 

Brass  condenser  tubes  should  be  made  of  copper  70,  zinc 
30,  as  prescribed  by  the  British  Admiralty.  Boiler  tubes  are 
made  of  copper  18,  zinc  32.  The  metals  should  be  pure. 

In  many  cases  peculiar  and  ornamental  shapes  are  given 
by  modification  of  the  form  of  mandrel  or  of  draw-plates. 
Patterned  sheets  are  produced  by  the  use  of  rolls  with 


BRASSES  AND  OTHER  COPPER-ZINC  ALLOYS.  165 

properly  cut  surfaces.  The  "  die"  in  which  the  metal  is  given 
shape  under  the  blows  of  a  "  drop,"  or  of  a  heavy  hammer, 
is  very  extensively  used  in  working  brass. 

92.  The  Properties  of  Brasses,  as  described  by  the  best 
authorities,  are  exhibited  in  the  most  concise  manner  in  the 
following  table,  which  was  originally  collated  for  the  Com- 
mittee on  Alloys  of  the  U.  S.  Board,*  as  was  that  already 
given  for  the  bronzes.  It  includes  the  results  of  work  done 
for  that  board. 

A  more  complete  exhibit  of  the  mechanical  properties  of 
the  bronzes  and  brasses  will  be  given  in  succeeding  chapters 
describing  investigations,  usually  conducted  by  the  Author, 
as  above. 

*  Report,  vol.  ii,  1881,  p.  67. 


1.66  MATERIALS  OF  ENGINEERING-NON-FERROUS  METALS. 


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BRASSES  AND  OTHER  COPPER-ZINC  ALLOYS.  167 

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1 68     MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE  XXII.  —  Continued. 

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BRASSES  AND  OTHER  COPPER-ZINC  ALLOYS. 


169 


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LIST  OF  AUTHORITIES. 
Bo.  —  Bolley.  Essais  et  rccherches  chimiques,  Paris,  1869. 
Cr.—  Croockewit.  Erdmann's  Journal,  xlv.,  1848.  pp.  87-93. 
C.  J.—  Calvert  and  Johnson.  Phil.  Ma%.,  18.  1850.  pp.  3^4-359;  ibid.,  17,  1859,  pp.  114-121  :  ibid.,  16,  1858,  pp.  381-383. 
Ma.-Matthiessen.  Phil.  Trans.,  1860.  pp.  161-184  ;  ibid.,  1864,  pp.  167-200. 
Ml.—  Mallet.  Phil.  Mag.,  v.  21,  1842,  pp.  66-68. 
Ri.  —  Riche.  Annales  de  chimie,  30,  1873,  pp.  751-410. 
U.  S.  B.—  Report  of  Committee  on  Metallic  Alloys  of  United  States  Board  appointed  to  test  iron,  steel,  etc.  (Thurston's  Investigations). 
We.  —Weidemann.  Pogg.  Annalcn,  108,  1859,  pp.  393-407. 

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MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Note  on  the  Table. — Alloys  having  the  name  of  Bol- 
ley  appended,  are  taken  from  Bolley's  "  Essais  et  Recherches 
Chimiques,"  which  gives  compositions  and  commercial  names, 
and  mentions  valuable  properties,  such  as  are  given  in  the 
columns  of  remarks,  but  does  not  give  results  in  figures,  as 
recorded  by  other  authorities.  The  same  properties  and  the 
same  name  are  accorded  by  Bolley  to  alloys  of  different  com- 
positions, such  as  those  which  in  the  column  of  remarks  are 
said  to  be  "  suitable  for  forging."  It  might  be  supposed  that 
such  properties  belonged  to  those  mixtures  and  not  to  other 
mixtures  of  similar  composition.  It  seems  probable,  how- 
ever, that  v/hen  two  alloys  of  different  mixtures  of  copper 
and  zinc  are  found  to  have  the  same  strength,  color,  fracture, 
and  malleability,  it  will  also  be  found  that  all  alloys  between 
these  compositions  will  possess  the  same  properties,  and 
hence  that,  instead  of  the  particular  alloys  mentioned 
only  being  suitable  for  forging,  all  the  alloys  between 
the  extreme  compositions  mentioned  also  possess  that 
quality. 

In  the  figures  given  from  Mallet  under  the  heads  of  "  order 
of  ductility,"  "  order  of  malleability,"  "  hardness,"  and  "  order 
of  fusibility,"  the  maximum  of  each  of  these  properties  is  re- 
presented by  i. 

The  figures  given  by  Mallet  for  tenacity  are  confirmed  by 
experiments  of  the  Author,  with  a  few  very  marked  excep- 
tions. These  exceptions  are,  chiefly,  the  figures  for  copper, 
for  zinc,  and  for  CuZn2  (32.85  copper,  67.15  zinc).  The  figures 
for  CuZn2,  as  given  by  Mallet,  can,  in  the  opinion  of  the  Author^ 
only  be  explained  on  the  supposition  that  the  alloy  tested  was 
not  CuZn2  (32.85  copper,  67.15  zinc),  but  another,  containing 
a  percentage  of  copper  probably  as  high  as  55.  The  figure 
for  the  specific  gravity  (8.283)  given  by  Mallet,  indicates  this 
to  be  the  case,  as  does  the  color.  The  figure  for  ductility 
would  indicate  even  a  higher  percentage  of  copper.  The 
name  "  watchmaker's  brass  "  in  the  column  of  remarks  must 
be  an  error,  as  that  alloy  is  a  brittle  silver-white,  and  ex- 
tremely weak  metal. 

The  figures  of  Calvert  and  Johnson  and  Riche,  as  well  as 


BRASSES  AND  OTHER  COPPER-ZINC  ALLOYS.  I /I 

those  of  the  Author,  give  a  more  regular  curve  than  can  be 
constructed  from  the  figures  of  Mallet. 

The  specific  gravities  in  Riche's  experiments  were  obtained 
both  from  the  ingot  and  from  powder.  In  some  cases  one, 
and  in  some  cases  the  other,  gave  highest  results.  In  the 
table,  under  the  head  of  "  specific  gravity,"  Riche's  high- 
est average  figures  are  given,  whether  these  are  from  the 
ingot  or  from  fine  powder,  as  probably  the  most  nearly  cor- 
rect. The  figures  by  the  other  method,  in  each  case,  are 
given  in  the  column  of  remarks.  The  figures  of  Riche  and 
Calvert  and  Johnson  are  scarcely  sufficient  in  number  to  show 
definitely  the  law  relating  specific  gravity  to  composition,  and 
the  curves  from  their  figures  vary  considerably.  The  figures  of 
the  Author  being  much  more  numerous  than  those  of  earlier 
experimenters,  a  much  more  regular  curve  is  obtained,  es- 
pecially in  that  portion  of  the  series  which  includes  the  yel- 
low, or  useful  metals.  The  irregularity  in  that  part  of  the 
curve  which  includes  the  bluish-gray  metals  is,  no  doubt,  due 
to  blow-holes,  as  the  specific  gravities  were  in  all  cases  deter- 
mined from  pieces  of  considerable  size.  If  it  were  determined 
from  powder,  it  is  probable  that  a  more  regular  set  of  obser- 
vations could  be  obtained,  and  that  these  would  show  a  higher 
figure  than  7.143,  that  obtained  for  cast  zinc.  Matthiessen's 
figure  for  pure  zinc,  7.148,  agrees  very  closely  with  that  ob- 
tained by  the  Author  for  the  cast  zinc,  which  contained  about 
I  per  cent,  of  lead. 

The  figures  for  hardness  given  by  Calvert  and  Johnson  were 
obtained  by  means  of  an  indenting  tool.  The  figures  are  on 
a  scale  in  which  the  figure  for  cast  iron  is  taken  as  1,000. 
The  alloys  opposite  which  the  word  "  broke  "  appears,  were 
much  harder  than  cast  iron,  and  the  indenting  tool  broke 
them  instead  of  making  an  indentation.  The  figures  of  al- 
loys containing  17.05,  20.44,  25-52»  an<^  33-94  Per  cent-  zinc, 
have  nearly  the  same  figures  for  hardness,  varying  only  from 
427.08  to  472.92.  This  corresponds  with  what  has  been  stated 
by  the  Author  in  regard  to  the  similarity  in  strength,  color, 
and  other  properties  of  alloys  between  these  compositions. 


CHAPTER   VI. 

THE   KALCHOIDS   AND    MISCELLANEOUS   ALLOYS. 

93.  Other  Alloys  than  Bronzes  and  Brasses  exist  in  im« 
mense  variety  and  have   numerous  applications  in  the  Arts, 
although  of  far  less  common  application  than  the  classes  of 
alloys  already  described. 

Of  these  alloys,  the  most  important  are  those  which  most 
closely  resemble  the  true  bronzes  and  brasses  in  composition, 
as  alloys  consisting  of  bronze  or  brass  with  which  are  united 
smaller  proportions  of  lead,  iron,  nickel,  antimony,  bismuth, 
and  other  common  metais.  In  this  class  also  fall  the  "Kal- 
choids"  as  the  Author  would  call  them,  or  the  copper-tin-zinc 
alloys  which  are  usually  called  brass  or  bronze  accordingly 
as  zinc  or  tin  predominates.  The  white  "  anti-friction  "  or 
"anti-attrition"  metals,  the  fusible  alloys,  and  type  and 
stereotype  metals,  all  come  within  this  classification. 

94.  The   Kalchoids   (Gr.    Kalchos\    or    Copper-Tin-Zinc 
Alloys,  are  of  great  value   and   include    the  strongest,   and 
probably  the  hardest,  possible  combinations  of  these  metals. 
They  are,  in  most  respects,  usually,  intermediate  between  the 
brasses  and  the  bronzes  obtained  by  uniting  two  metals. 

According  to  MargrafT,  these  alloys  are  often  very  valu- 
able and  have  the  character  as  per  table  on  next  page. 

Mackensie  finds  the  alloy,  copper  58,  zinc  25,  tin  17, 
excellent  for  castings  and  a  good  statuary  bronze;  and  pro- 
poses copper  50,  zinc  22,  tin  28,  for  mirrors  for  telescopes ; 
it  is  slightly  yellow  and  takes  a  very  fine  polish.  Bronzes  in 
which  equal  parts  tin  and  zinc  are  used  are  of  common  use 
for  very  small  articles — as  u  brass  "  buttons.  Knives  for 
cotton  printers'  rolls  are  often  made  of  copper  82,  zinc  10, 
tin  8.  Depretz'  "  chrisocalle  "  is  of  copper  92,  tin  6,  zinc  6, 


KALCHOIDS  AND  MISCELLANEOUS  ALLOYS. 


173 


it  has  a  beautiful  golden  color.  Another  composition  imitat- 
ing gold  is,  copper  81.5,  zinc  8,  tin  0.5  ;  and  still  another, 
which  retains  its  lustre  well,  is  of  copper  80,  zinc  17,  tin  3; 
it  is  used  for  the  small  parts  of  ornamented  pistols,  etc. 
Alloys  containing  these  metals  are  used  for  bronze  medals, 
the  zinc  and  tin  being  introduced  to  the  extent  of  from  2  to 
8  per  cent,  and  the  total  of  both  being  usually  10  per  cent,  or 
less.  The  percentage  of  zinc  is  usually  kept  under  3  or  4  in 
ordnance  metal. 


TABLE   XXIII. 

COPPER-TIN-ZINC  ALLOYS. 


NO. 

COPPER. 

TIN. 

ZINC. 

REMARKS. 

I 

IOO 

IOO 

IOO 

Very  white,  brittle,  subject  to  liquation. 

2 

100 

50 

50 

but  finer  grain. 

3 

IOO 

25 

50 

Yellowish  tint,  hard,  fine,  not  malleable. 

4 

IOO 

25 

25 

Brittle. 

5 

IOO 

20 

20 

Brittle,  hard,  yellow. 

6 

IOO 

16 

16 

"       close  grained. 

7 

IOO 

14 

14 

Yellow,  slightly  malleable. 

8 

IOO 

12.5 

12.5 

"       more  malleable. 

9 

IOO 

ii 

II 

«           «           « 

10 

IOO 

10 

10 

Fine  yellow,  fine  grain,  malleable. 

ii 

IOO 

8 

8 

Yellow,  softer,  more  malleable. 

12 

IOO 

7 

7 

Golden,  malleable,  soft. 

13 

IOO 

6 

6 

<<               «             « 

The  use  of  8  to  15  per  cent,  of  tin  and  2  per  cent,  zinc  in 
alloy  with  copper  is  probably  as  common  as  the  employment 
of  the  bronzes  without  zinc ;  the  latter  is  added  to  improve 
the  color.  Alloys  of  copper  containing  from  3  to  8  or  10  per 
cent,  zinc  and  from  8  to  15  per  cent,  tin  are  used  in  engineer- 
ing very  extensively,  the  softer  alloys  for  pump-work,  the 
harder  for  turned  work  and  for  nuts  and  bearings.  An  alloy 
of  5  per  cent,  tin,  5  zinc  and  90  copper  is  cast  into  ingots  and 
remelted  for  general  purposes.  It  is  tough,  strong  and 
sound.  Copper  75,  tin  12,  zinc  3  makes  a  good  mixture  for 
heavy  journal-bearings.  Copper  76,  tin  12,  zinc  12,  is  as  hard 
as  tempered  steel  and  was  made  into  a  razor-blade  by  its 


1/4  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

discoverer,  Sir  F.  Chantrey.*  When  copper  and  brass  are 
mixed  in  equal  proportions  and  their  sum  is  equal  to  the 
weight  of  tin,  the  alloy  constitutes  a  solder. 

95.  Copper,  Zinc  and  Iron  unite  with  some  difficulty,  and 
the  presence  of  iron  is  thought   to  make  brass  harder,   to 
weaken  it,  and  to  increase  its  liability  to  tarnish.     A  ternary 
alloy  of  this  character  was  introduced  in  England  as  early  as 
1822  and  was  claimed  to  be  stronger  and  better  for  the  pres- 
ence of  the   iron.     An  alloy  of   I   per  cent,  brass  with  99  of 
iron  was  advised  for  castings  exposed  to  corrosion,  and  Kars- 
ten  found  that  it  was  harder  than  the  cast  iron,  and  considered 
it  well  adapted  for  use  in  steam  engine  cylinders  and  heavily 
loaded  journal  bearings.      Herve  found  the  zinc  less  desira- 
ble in   copper-iron   alloys  than    tin.     He  states   that   alloys 
containing  1.33  to  4  per  cent,  copper  and  0.65  to  3  per  cent, 
zinc  were  stronger  than  the  cast  iron  with  which  they  were 
alloyed.    Sterro-metal,  elsewhere  described,  is  a  metal  of  this 
kind,  containing  also  a  small  amount  of  tin. 

96.  Copper,  Tin  and  Iron  may  be  alloyed  to  make  a 
ferrous  bronze  of  great  value.     The  introduction  of  cast-iron 
into  gun-bronze   (copper  89,  tin   n,  or   copper  90,  tin    10)  is 
not  only  useful,  in  small  amounts  as  a  flux,  but  this  ferrous 
alloy  is  harder  and  stronger  than   the  bronze  alone.     This 
alloy  was  made   in  Russian  arsenals  about  1820—5,  and  used 
for  ordnance.     The  maximum   proportion  of  iron  was  from 
12  to  25  per  cent.,  according  to  the  use  intended.     The  guns 
made  of  these   alloys  were  found,  according  to   Depretz,  to 
excel  good  gun-bronze  ordnance  in  strength   and   endurance. 
Similar  alloys  were  made  in  France  by  the  Messrs.  Darcet  f 
and  by  M.  Dussaussoy,  of  the  artillery,  and  on  a  large  scale,  in 
the  government  foundry  at  Douai. 

The  latter  experiments  were  made  with  alloys  containing : 


Copper. 

Tin. 

Iron. 

Copper. 

Tin. 

Iron. 

90 

10 

6 

9° 

10 

4 

90 

10 

3 

*  Holtzapffel. 

\  Alliages  Metalliques,  p.  333. 


KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.  175 

The  results  were  not  such  as  to  lead  to  the  adoption  of 
these  alloys  in  making  field  guns. 

Wrought  iron  was  introduced  into  standard  gun-bronze 
by  Dussaussoy  as  early  as  1817,  using  tin-plate  for  the  pur- 
pose. When  the  proportion  of  iron  exceeded  2  per  cent,  the 
result  was  not  satisfactory.  For  small  articles,  the  ferrous 
bronze  was  found  an  improvement,  it  being  stronger,  harder 
and  less  fusible.  Gen.  Goguel,  of  the  Russian  Army,  added 
12  per  cent,  of  wrought  iron  to  gun-bronze,  and  reported  that 
the  ordnance  made  of  this  alloy  proved  much  superior  to  that 
made  of  common  gun-bronze.  Subsequently,  an  extended 
investigation  was  made  by  the  order  of  the  French  govern- 
ment by  MM.  Gay  Lussac  and  Darcet,  and  later  by  M. 
Herve  of  the  French  Artillery.  The  former  research  led  to 
no  result ;  the  last  named  investigator  concluded  that  the 
use  of  tin  in  securing  an  alloy  of  iron  with  copper  is  of  ad- 
vantage and  that  re-fusion  is  advisable  to  secure  the  best 
results. 

97.  Manganese  Bronze  is  said  to  have  qualities  resem- 
bling those  of  phosphor-bronze,  the  introduction  of  man- 
ganese increasing  the  strength,  ductility  and  homogeneous- 
ness  of  the  alloy.  The  manganese  alloys  are  usually 
white  tinged  with  red,  ductile,  hard  and  tenacious.  They 
are  often  known  as  white  brass,  white  bronze  or  white  alloys ; 
they  take  a  fine  polish  ;  those  richest  in  copper  have  a 
decided  rose  hue.  These  alloys,  as  well  as  the  phosphor- 
bronzes,  are  in  somewhat  extensive  use,  especially  in  Great 
Britain. 

Copper  and  manganese  alloy  easily,  or  with  difficulty,  under 
different  conditions,  making  a  metal  of  considerable  mallea- 
bility, red  in  color,  turning  green  when  weather  stained.  It 
is  less  fusible  than  copper,  lighter  in  color,  and  more  liable  to 
tarnish  ;  it  may  be  made  by  fusing  together  copper  and  the 
black  oxide  of  manganese.  Manganese  bronze  contains 
iron,  also,  and  is  made  by  melting  together  copper  and  spie- 
geleisen  or  "  ferro-manganese."  When  containing  10  per 
cent,  manganese,  the  alloy  of  copper  and  this  metal  is  dense, 
grayish-white  with  a  tinge  of  red,  very  ductile  and  malleable. 


176  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

and  of  rather  a  short  fracture ;  with  20  per  cent,  manganese, 
the  color  is  silver-white  to  tin  white,  strong  and  ductile,  with 
a  fine  lustre ;  with  30  per  cent,  manganese,  the  properties 
remain  little  altered ;  with  40  per  cent.,  the  alloy  becomes 
iron-gray,  malleable  and  ductile,  very  strong,  fracture  inclined 
to  fibrous.  Thus,  according  to  Berthier,  all  these  alloys  are 
ductile,  strong,  compact  and  homogeneous. 

Manganese-bronze  is  very  similar  in  its  general  character- 
istics to  phosphor-bronze ;  but  is  a  white  alloy  and  differs  in 
being  a  triple  compound  of  the  metals,  copper,  tin  and  man- 
ganese, instead  of  an  alloy  of  copper  and  tin  fluxed  with  a 
metalloid.  It  possesses  some  peculiarities  which  give  very 
great  value  to  this  metal  as  a  material  of  construction.  It  is 
remarkably  hard,  tough  and  elastic,  has  rather  a  high  elastic 
limit,  as  compared  with  ordinary  bronze,  and  is  found  to  be  very 
durable  when  used  for  bearings  of  machinery.  A  common  pro- 
portion of  its  constituents  is,  copper,  88,  tin,  10,  manganese,  2. 

98.  Preparation  and  Uses  of  Manganese-Bronze. — As 
described  by  the  inventor,  Mr.  P.  M.  Parsons,  white  bronze, 
or  manganese-bronze,  is  prepared  by  combining  ferro-man- 
ganese,  in  different  proportions,  with  various  bronze  alloys, 
thus  producing  qualities  suited  to  various  uses.  The  ferro- 
manganese  is  first  subjected  to  a  refining  process,  by  which 
the  silicon  is  eliminated,  and  the  proportion  between  the  iron 
and  manganese  adjusted  in  various  degrees,  for  use  according 
to  the  quality  of  bronze  to-be  produced.  To  effect  this  com- 
bination, the  temperature  of  the  copper  must  be  brought  up 
to  the  melting  point  of  the  ferro-manganese,  which  is  melted 
separately  and  then  added  in  a  fluid  state. 

The  effect  of  this  combination  is  similar  to  that  produced 
by  the  addition  of  ferro-manganese  to  decarbonized  iron  in 
the  Bessemer  converter.  The  manganese  in  its  metallic  state 
having  a  strong  affinity  for  oxygen,  cleanses  the  copper  of 
oxides,  and  renders  the  metal  more  dense  and  homogeneous. 
A  portion  of  the  manganese  is  utilized  in  this  manner,  while 
the  remainder,  with  the  iron,  becomes  permanently  combined 
with  the  copper,  and  plays  an  important  part  in  improving 
and  modifying  the  quality  of  the  bronzes  prepared  from  the 


KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.  1 77 

copper  thus  treated,  the  effect  being  to  increase  their  strength, 
hardness,  toughness  in  various  degrees,  according  to  the 
quality  and  quantity  of  the  ferro-manganese  employed. 
Manganese,  when  once  incorporated  with  the  copper,  is  not 
driven  off  by  remelting ;  the  quality  of  the  manganese-bronze 
is  improved  by  remelting. 

Manganese-bronze,  as  is  stated,  when  forged,  is  remarkable 
for  its  strength  and  toughness,  having  an  average  tensile 
strength  equal  to  mild  steel,  and  elongating  as  much  before 
breaking.  It  is  suitable  for  forgings  of  all  kinds,  for  bolts 
and  nuts  for  engine  and  machine  work,  for  ships'  bolts,  rud- 
der and  other  fittings,  screws,  pins,  nails,  pump-rods,  wire, 
and  for  all  purposes  for  which  yellow  metal,  brass,  and  cop- 
per are  employed.  In  forging  this  metal,  it  should  be  heated 
to  a  clear  cherry  red  (not  bright),  when  it  may  be  hammered, 
rolled,  pressed,  or  worked  in  any  way  as  long  as  it  retains 
any  color.  It  should  not  be  worked  at  a  black  heat,  but 
when  the  color  is  just  fading  it  should  be  reheated. 

In  rolled  sheets  and  plates  it  can  be  worked  both  hot  and 
cold.  In  working  hot,  the  instructions  given  for  forgings 
should  be  followed.  The  metal  can  be  rolled,  stamped, 
pressed,  and  worked  cold  like  brass  or  copper,  being  annealed 
as  required.  It  is  stronger,  stiffer,  and  harder  than  copper, 
brass,  or  yellow  metal,  for  which  it  can  be  substituted  for 
purposes  to  which  these  are  applied. 

The  rods,  plates,  sheets  and  angles  are  supplied  of  mild, 
medium,  or  high  qualities,  as  required.  The  mild  and  medium 
qualities  have  a  tensile  strength  of  28  tons  per  square  inch 
(4,410  kgs.  per  sq.  cm.),  with  an  elastic  limit  at  40  per  cent, 
and  stretch  from  28  to  45  per  cent,  before  breaking.  These 
qualities  can  be  worked  and  riveted  up  cold,  and  are  claimed 
to  be  greatly  superior  to  yellow  metal  or  gun  metal. 

When  ships'  screws  are  made  of  this  material,  they  are 
given  less  thickness  than  when  made  of  mild  steel  or  of  com- 
mon bronze;  it  is  not  subject  to  alteration  of  form  when 
taken  from  the  mould  or  by  the  annealing  which  must  be 
done  with  steel  castings  ;  it  retains  a  clean  surface  remarkably 
well,  but  its  cost  is  considerable. 

12 


1/8  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

The  ferro-manganese  used  to  mix  with  gun  metal  con- 
tains from  10  to  40  per  cent,  of  metallic  manganese ;  with 
brass  alloys,  5  to  20  per  cent.,  and  with  bronze  alloys,  the 
proportion  lies  between  the  above,  according  to  the  propor- 
tions of  tin  and  zinc  employed.  To  prepare  ferro-manganese 
containing  a  given  amount  of  metallic  manganese,  the  invent- 
or melts  rich  ferro-manganese,  containing  up  to  70  per  cent., 
in  a  crucible  under  powdered  charcoal,  and  with  a  quantity  of 
the  purest  wrought-iron  scrap.  If  it  is  desired  to  employ  a 
ferro-manganese  to  mix  with  any  of  the  alloys  containing  20 
per  cent,  of  manganese,  a  ferro-manganese  containing  60  per 
cent,  of  metallic  manganese,  and,  say,  I  per  cent,  of  silicon, 
is  melted  with  wrought-iron  scrap,  in  the  proportion  of  100 
of  ferro-manganese  to  300  scrap.  Then  a  ferro-manganese 
containing  20  per  cent,  of  metallic  manganese  will  be  ob- 
tained, in  which  there  is  only  one-third  of  I  per  cent,  of 
silicon. 

Dry  sand  or  loam  moulds  are  recommended  for  casting. 
Metal  moulds  render  the  alloy  somewhat  harder  and  closer  in 
texture. 

Manganese-bronze  is  said  to  be  much  less  subject  to  cor- 
rosion.in  salt  water  than  is  pure  copper.  Alloys  containing 
from  75  to  85  per  cent,  copper  are  most  usually  adopted  for 
machinery.  Zinc  often  forms  a  constituent  of  these  alloys,  in 
the  proportion  of  from  2  to  10  per  cent. 

The  addition  of  manganese  to  bronzes  and  brasses  gives 
them  much  lighter  color,  greater  hardness  and  tenacity,  with- 
out proportionally  decreasing  ductility  and  resilience.  Cop- 
per and  manganese  alone  form  white  alloys  of  great  hardness, 
strength  and  ductility.  Some  of  these  alloys  forge  well  and 
can  be  rolled  with  ease.  They  are  somewhat  susceptible 
to  the  action  of  the  atmosphere  at  high  temperature,  and 
should  be  worked  as  little  and  at  as  low  temperature  as  pos- 
sible. 

99.  Aluminium- Bronze. — Aluminium  is  added  to  copper 
and  to  the  bronzes  and  brasses  with  good  results.  The  alloy, 
copper  90,  aluminium  10,  may  be  worked  cold  or  hot  like 
wrought  iron,  but  not  welded.  Its  tenacity  is  sometimes 


KALCHOIDS  AND  MISCELLANEOUS  ALLOYS. 


179 


nearly  100,000  pounds  per  square  inch  (7,030  kilos  per  square 
mm.),  and  its  average  is  not  far  from  three-fourths  as  great. 
It  is  hard  and  stiff  and  very  homogeneous.  Wire  has  been 
given  a  tenacity  exceeding  125,000  pounds  per  square  inch 
(8,776  kilos  per  square  mm.).  Its  specific  gravity  is  7.7.  In 
compression  this  alloy  has  been  found  capable  of  sustaining  a 
little  more  than  in  tension  (130,000  pounds  per  square  inch, 
9,139  kilos  per  square  mm.),  and  its  ductility  and  toughness 
were  such  that  it  did  not  even  crack  when  distorted  by 
this  load.  It  is  so  ductile  and  malleable  that  it  can  be  drawn 
down  under  the  hammer  to  the  fineness  of  a  cambric  needle. 
Measuring  its  stiffness,  the  Messrs.  Simms  found  *  that  it  had 
three  times  that  of  gun -bronze  and  44  times  that  of  brass. 
It  works  well,  casts  well,  holds  a  fine  surface  under  the  tool, 
and  when  exposed  to  the  weather ;  and  it  is,  in  every  respect, 
considered  the  best  bronze  yet  known.  Its  high  cost  alone 
prevents  its  extensive  use  in  the  arts.  Alloying  2  to  8  per 
cent,  copper  with  aluminium  raises  its  tenacity  65  to  90  per 
cent.,  making  it,  weight  for  weight,  stronger  than  machinery 
steel,  f  Pure,  it  has  a  tenacity  of  about  30,000  Ibs.  per  square 
inch,  and  a  modulus  about  11,000,000. 

The  density  of   aluminium-bronze    has   been  determined 
by  M.  Riche,J  with  the  following  results: 

BRONZE   CONTAINING   TEN   PER   CENT.    OF   ALUMINIUM. 


DENSITY. 

I. 
WT.  =  120^.568. 

II. 

WT.   =  120^  .275. 

After  casting 

7.705 
7.706 
7.706 
7-707 
7-703 
7.703 
7.701 
7.699 

7.704 
7.704 
7.705 
7.707 
7.704 
7.702 
7-702 
7.703 

After  tempering  

After  tempering             . 

After  annealing      

After  tempering                                           .  . 

After  impact  

*  Ure's  Diet..  Art.  Aluminium. 

f  Rail-way  Review,  Jan.  7,  1891. 

£  Ann    de  Chimie,  vol.  xxx.,  1873,  pp.  351-419. 


Appendix. 


180  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


BRONZE  CONTAINING    FIVE    PER   CENT.    OF   ALUMINIUM. 


. 

DENSITY. 

I. 

\VT.  =  129".  575. 

II. 
WT.  —  I29*r  .l6l. 

After  casting^ 

8.252 
8.259 
8.255 
8.257 
8.257 
8.264 
8.263 
8.263 

8.262 
8.259 
8.262 
8.262 
8.262 
8.264 
8.264 
8.265 

After  tempering     .      ..              

After  tempering 

After  annealing  

After  tempering                                    .  .  • 

After  impact   

Tempering,  annealing,  and  mechanical  action  produce  no 
noticeable  variation  in  the  volume. 

These  alloys  are  very  uniform  in  character  and  work  regu- 
larly and  smoothly. 

100.  Uses  of  Aluminium-Bronze. — Aluminium-bronze, 
composed  of  9  parts  copper  and  I  part  aluminium,  was  pro- 
posed in  1864  as  a  material  for  small  coins,  and  with  this  ob- 
ject in  view  the  assayer  of  the  United  States  mint  made  a 
number  of  careful  experiments  with  it.  The  assayer  states 
that  aluminium-bronze  possesses  much  greater  hardness  than 
copper  alone,  but  less  malleability  and  ductility.  When 
rolled  into  sheets,  it  requires  annealing  at  every  third  pas- 
sage through  the  rolls ;  when  drawn  into  wire  it  must  also  be 
frequently  annealed.  To  strike  a  coin  of  this  bronze  required 
unusual  force.  It  tarnishes  quite  readily,  but  not  more  so 
than  copper. 

Aluminium-bronze  containing  ^/^  per  cent,  of  aluminium 
is  greenish  in  color,  according  to  Morin,  while  other  compo- 
sitions on  either  side  are  golden.  Even  I  per  cent,  added  to 
copper  causes  a  considerable  increase  in  ductility  and  fusi- 
bility, and  enables  it  to  be  used  satisfactorily  in  making 
castings.  Two  per  cent,  gives  a  mixture  used  for  castings 
which  are  to  be  worked  with  a  chisel.  The  standard  alumin- 
ium-bronze— 10  per  cent,  aluminium — is  brittle  after  the 
first  fusion,  but  becomes  more  ductile  as  well  as  stronger  by 
repeated  refusion.  It  makes  good  castings,  is  easily  worked, 


KALCHOIDS  AND  MISCELLANEO US  ALLO  VS.  1 8 1 

and  may  be  forged  at  a  red  heat,  and  is  fairly  ductile  under 
the  hammer  even  when  cold.  It  is  softened  by  sudden  cool- 
ing from  a  red  heat.  It  takes  a  fine  polish,  is  a  half  stronger 
than  good  wrought  iron  in  tension,  but  has  less  strength  in 
compression.  Its  coefficient  of  expansion  is  small  at  ordinary 
temperatures.  Its  liability  to  crack  in  large  masses  makes  it 
difficult  to  get  large  castings.  It  has  great  elasticity  when 
made  into  springs ;  it  is  found  useful  for  watches,  and  has  the 
decided  advantage  over  steel  of  being  but  little  liable  to  oxi- 
dation ;  the  addition  of  5  per  cent,  silver  is  advised  to  pure 
aluminium  to  make  springs.  Kettles  of  this  alloy  have  been 
used  in  making  fruit  syrup  and  preserves. 

The  alloy  of  aluminium  with  4  to  5  per  cent,  silver  is  used 
in  making  balances  for  chemists.  The  introduction  of  a  very 
minute  proportion  of  bismuth  makes  this  metal  very  brittle. 

Steel  containing  but  0.08  per  cent,  aluminium  is  said  to  be 
greatly  improved  by  its  presence. 

An  alloy  of  2  or  3  copper  and  97  or  98  aluminium  is  found 
useful  in  making  ornamental  silver-colored  castings  which  are 
to  be  chased  and  engraved. 

The  alloys  of  aluminium  and  copper  may  be  made  by  fus- 
ing together  the  oxides  with  metallic  copper  and  enough  car- 
bon and  flux  to  reduce  them.  The  oxides,  as  well  as  the 
other  materials,  should  be  as  finely  divided  as  possible,  and 
the  carbon  introduced  in  excess. 

101.  Copper  and  Nickel  are  quite  easily  alloyed,  giving 
a  metal  of  usually  white  color,  hard,  rather  brittle,  and  quite 
easily  oxidized.  When  the  nickel  forms  30  per  cent,  of  the 
whole,  the  alloy  is  easily  fused,  strong,  and  tough,  of  a  silvery- 
gray  color,  and  slightly  magnetic.  White  copper  and  Ger- 
man silver  consist  wholly  or  partly  of  this  alloy. 

Copper  and  nickel  unite  in  a  wide  .range  of  proportions. 
In  color  they  range  from  the  red  of  copper  to  the  blue-white 
of  nickel,  according  to  their  proportions.  Adding  nickel  in 
the  proportion  of  o.io,  the  alloy  is  very  ductile,  light  copper- 
red  in  color,  and  moderately  strong;  with  0.15  nickel,  the 
color  becomes  very  light  red  and  the  ductility  is  still  great ; 
0.25  nickel  gives  an  alloy  nearly  white;  0.30  nickel  produces 


182  MATERIALS  OF  ENGINEERING— NON-FERROUS  METAL*. 

a  silver-white  metal.  Berthier's  alloy,  copper  0.682,  nickel 
0.318,  is  fusible,  ductile,  strong,  bluish-white,  slightly  mag- 
netic and  somewhat  crystalline  near  the  surface. 

"  White  copper,"  so-called,  is  such  an  alloy,  usually  con- 
taining slight  quantities  of  iron  and  silicon. 

Nickel  coinage  is  now  used  by  several  nations ;  it  was 
first  privately  coined  by  Feuchtwanger,  of  New  York  City,  in 
1837;  Switzerland  began  using  it  in  1850,  the  United  States 
in  1857,  and  Belgium  in  1860.  The  U.  S.  coins  now  contain 
copper  75,  nickel  25. 

102.  German  Silver. — Copper,  zinc,  and  nickel  alloy 
readily.  These  compositions  were  used  at  a  very  early  date 
in  China,  and  have  been  known  as  packfong,  tutenag,  and 
white  copper.  The  East  Indian  or  Chinese  tutenag  is  a 
grayish-white  alloy,  somewhat  sonorous,  and  brittle.  Its 
composition  has  been  given  as  copper  44,  zinc  40,  nickel  16. 
The  other  alloys  above  named  are  nearly  silver-white,  malle- 
able hot  or  cold,  have  a  beautiful  lustre,  and  very  sonorous. 
The  specific  gravity  is  8.5.  Alloys  of  European  manufacture, 
of  similar  characteristics,  are  now  common.  Viennese  alloys 
have  been  found  by  Gersdorff  to  contain  :— 

Table  utensils  ;  copper,-  50  ;  zinc,  25  ;   nickel,  25. 
Ornaments  "        55  ;     "     25  ;        "       20. 

Sheet  metal  "        60;      "     20;        "       20. 

Prick's  alloys  contain  copper,  50  to  55;  zinc,  30  to  31; 
nickel,  17  to  19.  These  are  white  and  hard  but  ductile,  and 
have  a  specific  gravity  from  8.5  to  8.6 ;  they  are  used  in 
making  table  utensils  and  ornamental  objects.  The  alloy, 
copper  56,  zinc  5,  and  nickel  39,  makes  a  fine  white  metal  of 
the  same  class  with  the  preceding. 

German  sliver,  as  made  by  good  makers,  consists  usually  of 

Copper 60 

Zinc 20 

Nickel '. 20 

100 


KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.  183 

Guillemin  introduces  sodium,  thus: 

Copper 58.00 

Zinc 16.65 

Nickel 25.00 

Sodium o.  35 


Sound  castings  are  secured  by  the  use  of  borax,  glass,  or 
other  good  flux.  German  silver  is  rolled  cold,  and  the  rolls 
are  necessarily  made  of  very  great  strength  ;  frequent  anneal- 
ing is  necessary  during  the  process. 

103.  Copper  and  Iron  unite,  when  the  latter  is  in  small 
amount,  to  produce  a  stronger  metal  than  can  be  obtained 
without  the  iron,  even  when  the  copper  is  alloyed  with  other 
strengthening  elements ;  and  iron  forms  a  part  of  nearly  all 
manganese  bronzes,  of  the  bronze  known  as  Austrian  "  sterro- 
metal,"  and  of  various  other  useful  compositions.  The 
ductility  is  rather  improved  than  otherwise. 

Copper  and  iron  unite  at  high  temperatures,  if  the  heat  is 
sufficiently  prolonged,  and  in  any  proportions.  The  addition 
of  copper  to  iron  causes  brittleness,  or  "  red-shortness."  The 
Author  has  found  that  minute  doses  of  copper  confer  in- 
creased strength  on  some  steels,  and  Tredgold  states  that  the 
same  effect  is  observed  on  cast  iron.  Berthier  and  Rinmann 
think  that  one  per  cent,  copper  will  have  a  good  effect  on 
cast  iron. 

The  color  of  the  alloy  changes,  losing  the  gray  and 
becoming  red,  as  the  proportion  of  copper  increases,  up  to 
equal  parts  copper  and  iron,  when  the  alloy  loses  all  tint  of 
gray.  An  alloy  of  copper  66.67,  iron  33.33,  is  the  strongest  of 
these  alloys.  Mushet  has  made  a  number  of  these  alloys.  He 
finds  that  the  presence  of  carbon  causes  difficulty  in  making 
them.  Karsten  found  that  the  copper-iron  alloys  do  not  as 
readily  dissolve  in  sulphuric  acid  as  does  iron. 

A  ductile  alloy  was  made  by  Rinmann  of  copper  16,  iron 
I  ;  it  is  magnetic,  harder  than  copper,  and  the  fractured  sur- 
face has  a  beautiful  red  color.  Eight  parts  copper  and  from 


1 84  MATERIALS  OF  ENGINEERING-NON-FERROUS  METALS. 

I  to  4  parts  iron  produce  alloys  harder  than  the  preceding, 
but  not  appreciably  less  ductile  or  less  red  than  copper. 

Copper  and  cast  iron  alloy  to  form  a  strong  metal,  also. 

Riche  has  successfully  produced  alloys  of  copper  and 
iron ;  but  they  are  somewhat  variable  in  composition  and 
quality ;  thus : 

He  heated  in  a  temperature  sufficient  to  melt  cast  iron — • 

Copper 90 

Cast  iron 10 

The  ingot  obtained  contained,  at  the  top,  iron  uncom- 
bined. 

He  heated  very  hot  and  held  some  time  in  fusion — 

Copper 90 

Rivets 10 

The  ingot  obtained  furnished  upon  analysis — 

Top  1, 600  iron.. 

Bottom 365  iron. 

He  heated  very  hot  and  kept  melted  some  time — 

Copper 96 

Rivets 6 

The  metal  appeared  very  homogeneous.  Its  density, 
taken  at  two  different  points,  gave — 

8.881 
8.876 

The  metal  is  easily  forged,  stretches  and  coils  upon  itself 
without  breaking.  It  is  rolled  with  such  facility  that,  without 
annealing,  a  bar  of  it  can  be  reduced  from  a  thickness  of  9 
millimetres  (0.35  inch)  to  that  of  I  millimetre  (0.04  inch).  Its 
tenacity  exceeds  that  of  copper. 

Examining  with  a  magnifying  glass  the  plates  I  millimetre 
in  thickness  mentioned  above,  gray  spots  may  be  seen  at 
certain  points,  but  analysis  of  these  points  shows  no  material 


KALCHOIDS  AND  MISCELLANEOUS  ALLOYS. 


I8S 


difference   between    them    and   other  portions.     There   was 
found — 

Iron 5.383  5.285  5.236 

This  substance  made  very  hot  in  the  crucible  gives  a  but- 
ton in  which  there  remains  only — 

Iron 0.167  percent. 

These  two  metals  were  alloyed  in  variable  proportions, 
melted  in  earthen  tubes  15  centimetres  (5.9  inches)  in  length, 
and  after  being  kept  three  hours  in  fusion,  were  left  to  cool 
slowly.  Analysis  then  gave : — 


IRON,    PER   CENT. 


Top  of  bar. 

Bottom  of  bar. 

Density. 

I    

12  6q^ 

4-  (?4t? 

8.839  t°  8.771 

2 

92QO 

•*  680 

6  8?6 

J.UOU 

1.O52 

4    . 

4.6lQ 

4.  52O 

4.226 

4.288 

8.885 

6                                 .... 

2   Q^O 

2   6OO 

The  addition  to  copper  of  small  quantities  of  foreign 
matter,  iron,  for  example,  increases  the  porosity,  as  do  small 
quantities  of  oxygen.  The  copper  acquires  tenacity  and 
elasticity  by  this  addition  of  iron,  while  retaining  some  malle- 
ability. 

104.  Copper-Antimony  Alloys. — Antimony p,  added  to  the 
copper-tin  alloys,  rich  in  the  latter  metal,  is  largely  used  for  a 
lining  metal  in  journal-bearings.  Babbitt's  Metal  is  the  best 
known  of  these  metals,  and  contains  4  parts  copper,  96  of 
tin,  8  of  regulus  of  antimony.  It  is  made**  by  melting  4  parts 
of  copper,  adding  12  parts  best  tin,  8  of  regulus  of  antimony, 
then  12  of  tin  while  cooling  the  molten  mixture.  Of  this 
"  hardening  metal,"  one  part  is  added  to  twice  as  much  tin 
to  make  the  lining  metal.  Copper  I,  tin  9,  without  antimony, 
is  also  known  as  Babbitt  Metal ;  it  is  a  usual  composition  in 

*  Haswell. 


1 86  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 

government  work.  This  composition  has  been  found  ex- 
cellent in  locomotive  practice  and  more  satisfactory  than  that 
containing  antimony. 

Copper  and  antimony  alloy  in  the  proportion,  copper  85, 
antimony  15,  to  form,  according  to  Karsten,  a  brittle  metal 
of  little  value.  Equal  parts  copper  and  antimony  unite  to 
make  a  brittle,  light-violet  colored  alloy,  of  which  no  use  is 
made  in  the  arts. 

105.  Copper  and  Bismuth  unite  readily  and  at  a  temper- 
ature below  that  of  fusion  of  copper.     The  addition  of  bis- 
muth  causes  brittleness,  and  all  ductility  is  lost  when  the 
proportion  approaches   I    per  cent.     Minute  quantities  may 
be  added  to  copper,  and  if  not  above  0.5  per  cent,  the  alloy 
may  be  hammered   and  rolled ;  exceeding  that  proportion, 
the  alloy  becomes  brittle  with  working  and   too  much  so  to 
be   safely  used.      The  color  of   the   alloy  is   light    red ;  its 
density  is  the  mean   of  its  constituents.     Prince's  Metal  is 
said  to  be  an  alloy  of  copper  and  bismuth, 

106.  Bismuth-Bronze.  —  Webster's     bismuth-bronze    is 
made  of  various  proportions.     According  to  the  statement  of 
the  discoverer,  its  composition  and  qualities  are  as  follows : 

For  a  hard  alloy,  take  I  part  of  bismuth  and  16  parts 
of  tin,  both  by  weight,  and,  having  melted  them,  mix  them 
thoroughly.  For  a  hard  bismuth  bronze,  take  69  parts  of 
copper,  21  parts  spelter,  9  parts  nickel  and  I  part  of  the 
alloy  of  bismuth  and  tin.  This  bismuth-bronze  is  a  hard, 
tough  and  sonorous  metallic  alloy,  which  is  proposed  for 
use  in  the  manufacture  of  screw-propeller  blades,  shafts, 
tubes  and  other  appliances  employed  partially  or  constantly 
in  sea  water.  In  consequence  of  its  toughness  it  is  thought 
to  be  well  suited  for  telegraph  wires  and  other  similar  pur- 
poses where  much  stress  is  borne  by  the  wires.  From 
its  sonorous  quality  it  is  well  adapted  for  piano  and  other 
wires.  For  domestic  utensils  and  articles  exposed  to  at- 
mospheric influences,  use  I  part  bismuth,  one  part  aluminium 
and  15  parts  tin  melted  together  to  form  the  separate  or 
preliminary  alloy,  which  is  added  in  the  proportion  of  I  per 
cent,  to  the  above  described  alloy  of  copper,  spelter  and  nickel. 


KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.  1 87 

This  bronze  forms  a  bright  and  hard   alloy  suited  for  the 
manufacture  of  utensils  or  articles  exposed  to  oxidation. 

107.  Copper  and  Cadmium  form  an  alloy  similar  in  char- 
acter to  those  of  bismuth  and  copper. 

108.  Copper  and  Lead  unite  with  difficulty,  and  a  good 
alloy  can   only  be  obtained  with   a  small  quantity  of  lead. 
One-tenth  per  cent,  lead  gives  a  mixture  observably  less  duc- 
tile than  copper,  and  when  three  times  this  quantity  is  intro- 
duced the  alloy  has  the  singular  property  of  working  better 
cold  than  hot.     The  combining  temperature  is  so  high  that 
the  lead  usually  gives  off  fumes  of  oxide  ;  the  cooling  should 
be  done  rapidly.     The  alloy  has  a  lower  density  than  the 
mean  of  its  constituents  and  is  rarely  stable. 

An  alloy  of  copper  20,  lead  80,  is  sometimes  used  in  type- 
foundries  for  large  type.  This,  like  all  those  alloys,  if  kept 
in  a  state  approaching  that  of  fusion,  is  subject  to  separation 
or  "liquation,"  the  lead  separating  and  leaving  the  copper  in 
a  porous  mass.  When  the  alloy  oxidizes,  the  oxide  is  found 
to  contain  much  more  than  the  proportion  of  lead  contained 
in  the  alloy.  Common  "  pot-metal  "  contains  20  per  cent, 
lead.  It  is  brittle  when  heated  ;  larger  amounts  of  lead 
render  the  alloy  difficult  to  work  and  injure  it  seriously.  The 
fusibility  is  greatly  increased  by  the  presence  of  the  lead. 

Copper  and  lead  are  not  easily  alloyed,  but  form,  when 
combined,  a  metal  of  gray  color,  brittle,  and  of  feeble  affinity. 
An  alloy  of  lead  4,  copper  I,  is  sometimes  used  for  large  type. 
The  constituents  are  very  liable  to  separation,  when  kept 
molten,  by  liquation.  Norway  copper,  from  Drontheim,  con- 
tains a  half  per  cent,  lead  ;  it  is  preferred  in  making  brass. 
Other  coppers  often  contain  \l/2  or  2  per  cent.  lead. 

109.  Copper  and  Silicon,  with  or  without  tin,  may  be 
alloyed  to  form   "silicon-bronze."     Weiller's  alloy  is  made 
by  the  introduction  of  sodium  to  reduce  silica  in  the  cru- 
cible.    This   bronze   has   been    used   to    take  the   place   of 
phosphor-bronze  for  telegraph  wires  in  Southern  Europe. 

The  inventor  recommends  the  following  proportions  :  fluo- 
silicate  of  potash,  450  grams  ;  glass  in  powder,  600  grams ; 
chloride  of  sodium,  250  grams  ;  carbonate  of  soda,  75  grams; 


1 88  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

carbonate  of  lime,  60  grams ;  and  dried  chloride  of  calcium, 
500  grams.  The  mixture  of  these  substances  is  heated,  in  a 
plumbago  retort,  to  a  temperature  a  little  below  the  point 
when  they  begin  to  react  on  one  another,  and  it  is  then  placed 
in  a  copper  or  bronze  bath,  when  the  combination  of  the 
silicium  takes  place,  as  already  said. 

1 10.  Use  of  Silicon-Bronze. — The  superiority  of  silicon 
is  claimed  to  be  due  to  its  better  adaptability  to  being 
worked  at  a  high  temperature,  by  its  penetrating  the  metal 
better,  and,  consequently,  insuring  the  indispensable  homo- 
geneity. It  is  said  of  silicon-bronze,  that  it  possesses  the 
conducting  qualities  of  the  best  copper,  with  the  resisting 
qualities  of  the  best  iron,  and  that  each  of  these  advantages 
may  be  varied  at  will,  at  the  expense  of  the  other. 

Applied  to  aerial  telegraph  lines,  the  present  galvanized 
wires  of  the  great  lines,  5  millimetres  (0.2  inch)  in  diameter, 
and  weighing  155  kilos  per  kilometre  (120  pounds  per  mile), 
can  be  replaced  by  silicon-bronze  wires  of  2  millimetres  (0.08 
inch)  in  diameter,  weighing  only  26  kilos  to  the  kilometre 
(20  pounds  per  mile)  ;  while  the  ordinary  steel  telephone 
wires  of  2  millimetres  (0.08  inch)  diameter,  and  25  kilos  to 
the  kilometre  (20  pounds  per  mile),  may  be  replaced  by  sili- 
con wires  of  only  i^V  millimetre  (0.04  inch)  in  diameter,  and 
weighing  8  kilos  to  the  kilometre  (6  pounds  per  mile). 

in.  Copper,  Tin,  and  Lead  alloy  readily,  and  are  thus 
used  in  the  manufacture  of  art-castings,  for  which  purpose 
this  composition  was  also  used  by  the  ancients.  Statues  made 
by  the  Romans  have  been  found  to  contain  lead  in  a  propor- 
tion equal  to  about  one-fourth  that  of  the  tin.  Klaproth  finds 
in  an  antique  mirror,  copper  62,  tin  32,  lead  6.  The  pres- 
ence of  lead  in  bronze  is  usually  considered  objectionable. 

Bronzes  containing  2  to  15  per  cent,  lead  make  the  best 
of  bearings. 

112.  Copper,  Tin,  Antimony,  and  Bismuth  united,  form 
a  "  pewter,"  once  in  common  use  for  tableware  ;  it  is  a  beau- 
tiful alloy  resembling  silver,  but  too  readily  tarnished,  and 
too  soft  to  be  very  valuable.  It  contains  copper  3^,  tin 
88^,  antimony  7,  bismuth  I. 


KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.  189 

113.  Copper,  Tin,  Zinc,  and  Iron  are  found  in  bell  metal, 
and  make,  in  certain  proportions,  an  excellent  alloy.     The 
alloy  is  not  made  for  the  market.     The  above  metals,  alloyed 
with  nickel,  iorm"melchior"  a  composition   containing:  of 
copper,  55  ;  nickel,  23;  zinc,  17;  iron,  3;    tin,   2.  ^  Argenthal 
is   a   similar   metal.     They  are  white    alloys   and    used    for 
ornamental  castings.     Their  lustre  is  silvery  and  quite  per- 
manent. 

114.  Copper  and  Mercury  alloy  freely.     A  composition 
of  25  parts  copper  in  fine  powder,  obtained  by  precipitation 
from  solutions  of  the  oxide  by  hydrogen,  or  of  the  sulphate 
by  zinc,  washed  with  sulphuric  acid  and  amalgamated  with 
7  parts  of  mercury,  after  being  well  washed   and  dried,  is 
moderately  hard,  takes  a  good  polish,  and  makes  a  fine  solder 
for  low  temperatures.     It  will  adhere  to  glass. 

Droniers  malleable  bronze  is  made  by  adding  one  per  cent, 
of  mercury  to  the  tin  when  hot,  and  this  amalgam  is  carefully 
introduced  into  the  molten  copper. 

115.  Complex  Copper  Alloys. — An  alloy  imitating  gold 
is  made   thus :  Melt  together   pure    copper,  platinum,  and 
tungstic  acid,  in  proportion  as  follows :  Copper  800,  25   of 
platinum,   10  of  tungstic  acid,   175   of    gold.      When    com- 
pletely melted,  stir  and  granulate  by  running  into  water  con- 
taining 500  parts  of  slacked  lime,  and  the  same  of  carbonate 
of  potash  for  every  cubic  metre  of  water.     The  granulated 
metal  is  next  collected,  dried,  and,  after  remelting  in  a  cru- 
cible a  small  quantity  of  fine  gold  is  added.     An  alloy  results 
which,  when  run  into  ingots,  presents  the  appearance  of  red 
gold  of  the  standard  of  75o-ioooths,  bears  a  strong  acid  test, 
and  has  nearly  the  density  of  gold. 

A  so-called  unoxidizable  alloy  has  the  following  compo- 
sition :  Iron,  10  parts;  nickel,  35  parts;  brass,  25  parts;  tin, 
20  parts;  zinc,  10  parts.  The  castings  made  of  this  alloy  are 
cleaned  by  immersion,  while  white  hot,  in  a  mixture  of  60 
parts  sulphuric  acid,  10  parts  nitric  acid,  5  parts  hydrochloric 
acid,  and  25  parts  of  water. 

Alloys  of  copper,  tin,  zinc,  and  lead  are  the  most  familiar 
of  the  complex  alloys. 


1 90  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

116.  Bismuth  Alloys. — The  properties  of  alloys  of  bis- 
muth and  other  useful  metals  are  given  in  considerable  detail 
by  Guettier,  as  follows  : — * 

Alloys  of  Bismuth  and  Copper. — These  alloys  are  easily 
made,  notwithstanding  the  difference  in  the  points  of  fusion 
of  the  two  metals.  They  are  brittle,  and  of  a  pale  red  color, 
whatever  the  proportions  employed.  For  description  of  the 
useful  alloys  with  copper,  see  Articles  105-6,  page  1 86. 

Alloys  of  Bismuth  and  Zinc. — These  alloys  are  seldom 
made,  and  produce  a  metal  more  brittle,  exhibiting  a  larger 
crystallization,  with  less  strength,  than  zinc  or  bismuth  taken 
singly.  They  have  little  value  in  the  arts. 

Alloys  of  Bismuth  and  Tin. — The  combinations  of  bismuth 
and  tin  take  place  easily  and  in  all  proportions.  A  very  small 
quantity  of  bismuth  imparts  to  tin  more  hardness,  sonorous- 
ness, lustre,  and  fusibility.  On  that  account,  and  for  some 
purposes,  a  little  bismuth  is  added  to  tin  in  order  to  increase 
its  hardness.  But  bismuth,  being  easily  oxidized,  and  often 
containing  arsenic,  the  alloys  of  tin  and  bismuth  would  be 
dangerous,  if  used  for  the  manufacture  of  culinary  vessels. 
The  alloys  of  bismuth  and  tin  are  more  fusible  than  either  of 
the  metals  taken  separately.  An  alloy  of  equal  parts  of  the 
two  metals  is  fusible  between  a  temperature  of  100°  to  150° 
Centigrade  (2I2°-3O2°  F.).  When  tin  is  alloyed  with  as  little 
as  5  per  cent,  of  bismuth,  its  oxide  acquires  the  peculiar  yel- 
lowish-gray color  of  the  bismuth  oxide.  According  to  Rud- 
berg,  melted  bismuth  begins  to  solidify  at  264°,  and  tin  at 
288°  C.  (507°-55o°  F.).  For  the  alloys  of  the  two  metals  the 
"  constant  point  "  is  143°  C.  (289°  F.). 

Alloys  of  Bismuth  and  Lead. — These  two  metals  are  al- 
loyed by  simple  fusion,  with  ordinary  precautions.  The 
alloys  are  malleable  and  ductile  as  long  as  the  proportion  of 
bismuth  does  not  exceed  that  of  lead  ;  they  are  more  tena- 
cious than  lead.  The  alloy  of  bismuth  2  and  lead  3  is  ten 
times  harder  than  pure  lead.  The  compounds  of  bismuth 
and  lead  generally  have  a  dark  gray  color  with  a  tint  inter- 
mediate between  the  color  of  tin  and  that  of  lead.  Their 

*  Guettier  :  "  Guide  Pratique  des  Alliages  Metalliques."     Paris,  1865. 


KALCHOIDS  AND  MISCELLA 


fracture  is  lamellar,  and  their  specific  gravity  greater  than 
the  mean  specific  gravity  of  either  metal  taken  singly.  An 
alloy  of  equal  parts  of  bismuth  and  lead  has  a  specific  gravity 
of  10.71.  It  is  white,  lustrous,  sensibly  harder  than  lead,  and 
more  malleable.  The  ductility  and  malleability  diminish  with 
an  increased  proportion  of  bismuth,  while  they  increase  with 
the  excess  of  lead  in  the  alloy.  An  alloy  of  bismuth  I  and 
lead  2  is  very  ductile,  and  may  be  rolled  into  thin  sheets  with- 
out cracking.  Berthier  gives  its  point  of  fusion  as  166°  C. 

(331°  F.). 

Alloys  of  Bismuth  and  Iron.  —  Authorities  disagree  as  to 
the  possibility  of  combining  bismuth  and  iron.  The  presence 
of  bismuth  in  iron  tends  to  render  this  metal  brittle. 

Alloys  of  Bismuth  and  Antimony.  —  These  alloys  are  gray- 
ish, brittle,  lamellar,  like  the  alloys  of  bismuth  and  zinc,  and 
have  no  value  in  the  arts. 

It  will  be  seen  from  the  preceding  that  the  alloys  of  bis* 
muth  are  not  at  present  of  importance  in  the  arts,  excepting 
the  fusible  alloys  made  of  bismuth  and  certain  white  metals, 
such  as  tin,  lead,  etc.  The  alloys  of  bismuth  with  tin,  the 
latter  predominating,  are  the  most  interesting.  The  great  fusi- 
bility of  the  alloys  of  bismuth  and  lead  will  have  the  effect 
of  making  these  alloys  useful,  as  also  those  with  tin,  as  soon 
as  bismuth  can  be  obtained  in  abundance  and  at  small  cost. 

The  action  cf  the  bismuth  in  alloys  is  to  increase  their 
hardness,  fusibility,  and  brittleness.  But,  although  bismuth 
renders  brittle  the  metals  with  whicfi  it  combines,  it  does  so 
to  a  considerably  less  degree  than  either  arsenic  or  antimony. 

Tin  and  Bismuth  alloy  to  form  metals  of  greater  hardness, 
sonorousness,  and  fusibility  than  either  tin  or  bismuth.  Equal 
parts  give  an  alloy  which  melts  at  about  300°  F.  (150°  C. 
nearly),  and  is  called  "  cuttanego,"  of  which  the  oxide  makes 
a  white  enamel.  Tin  2,  bismuth  I,  gives  an  alloy  melting  at 
about  325°  F.  (165°  C.),  and  the  alloy  tin  8,  bismuth  I,  at 
480°  F.  (200°  C.).  Tin  itself  melts  at  about  440°  F.  (228°  C.), 
bismuth  at  510°  F.  (265°  C). 

Riche  gives  the  densities  of  alloys  of  tin  and  bismuth  as 
follows  : 


MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


THEORETICAL 
DENSITY. 

EXPERIMENTAL 
DENSITY. 

DIFFERENCE. 

REMARKS. 

Bi2  Sn 

94.26 

94^4 

+  .OO8 

Bi  Sn  

Q.  i  "35 

Q.  145 

+  .OIO 

Bi  Sn2  

V  *JJ 

8  740 

8.754 

+  .OI4 

Bi  Sn3 

8    4QI 

8.506 

+  .015 

Bi  Sn4  

8.qo6 

8.^27 

+  .021 

Bi  Sn5  

8.174 

8.  iqq 

+  025 

Maximum  contraction. 

Bi  Sn6     .    ... 

8   O7T 

8  007 

4-  .024 

7QQ4 

8  017 

+  .  O21} 

The  maximum  contraction  should  take  place  in  the  alloy 
Bi  Sn5,  which  is  a  silvery-white  metal  formed  of  little  crystal- 
line grains  commingled.  This  alloy  was  not  attacked  by  dis- 
tilled water ;  at  the  end  of  several  hours  it  retained  its  brill- 
iancy and  its  silvery  lustre. 

The  maximum  contraction  is  seen  with  the  alloy  Bi 
Pb3,  and  on  either  side  of  this  alloy  a  very  regular  diminution 
in  contraction  will  be  noticed.  The  differences  being  very 
great  both  between  the  theoretical  and  experimental  density, 
and  between  the  density  of  each  alloy  and  that  of  its  neigh- 
bors, he  made  but  two  determinations  for  each  alloy.  As 
analysis  of  the  ends  and  of  the  middle  of  the  ingot  formed  by 
the  alloy  BiPb3  gave  the  same  numbers,  it  seems,  therefore, 
that  this  alloy  should  be  considered  as  a  chemical  com- 
pound. 

Lead  and  bismuth  unite  readily,  when  fused,  to  form  a 
malleable  alloy  if  the  lead  is  in  excess,  but  a  brittle  compound 
if  the  bismuth  is  present  in  large  amount.  Its  color  is  dark 
gray,  fracture  often  lamellar,  and  the  density  greater  than 
that  given  by  calculation.  Equal  parts  give  an  alloy  having 
the  specific  gravity  10.71,  white,  lustrous,  harder  and  also 
even  more  malleable  than  lead;  with  lead  3,  bismuth  I,  an 
alloy  of  6  times  the  tenacity  of  lead  is  produced  ;  lead  2,  bis- 
muth i,  gives  a  very  malleable  alloy,  easily  rolled  into  thin 
sheets,  melting  at  325°  F.  (165°  C.),  the  melting-point  of  the 
alloy  of  equal  parts. 

Riche  finds  the  following  densities  of  alloys  of  lead  and 
bismuth  : 


THE  KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.       193 


Density  of  the  lead n .  364 

Density  of  the  bismuth 9. 830 


THEORETICAL 
DENSITY. 

EXPERIMENTAL 
DENSITY. 

DIFFERENCE. 

REMARKS. 

Bin  Pb 

lO.OQQ 

IO.232 

4-O    I*}** 

Bi  Pb  

IO.28S 

IO.  5IQ 

+  o  231 

Bi  Pb2  

10.  536 

IO    0^1 

+  O.3Q5 

Bia  Pb5  

10  622 

II  .038 

+  o  416 

Bi  Pbs  

IO.J.4S 

11.108 

+  O.66O 

Bi2  Pb7 

jo    74.8 

n  166 

•4-O  418 

Bi  Pb4     

IO   7Q7 

II.  IQ4 

+  O.  *}Q7 

Bi  Pbs  

10  874. 

II  .2OQ 

+  O.3*?5 

Bi  Pb«  

ro.0^2 

11.225 

+  O.293 

Bi  Pb7   

IO   Q7Q 

11.2*35 

+  O.254 

117.  Bismuth,  Tin,  and  Lead  form  a  series  of  "fusible 
alloys  "  used  in  obtaining  impressions  from  objects  made  of 
the  less  fusible  metals,  and  in  making  "  fusible  plugs  "  and 
other  safety  apparatus  or  gauges  of  temperature.  These  al- 
loys are  also  used  as  "  soft  solders.'* 

Newton's  alloy  consists  of  bismuth  50,  tin  30,  lead  20; 
it  melts  at  about  the  boiling-point  of  water.  These  alloys 
are  all  weak  and  are  of  a  dull  gray  color  and  tarnish  readily. 

Darcet's  alloys  are  the  following  : 

TABLE    XXIV. 
DARCET'S  FUSIBLE  ALLOYS. 


NO. 

BISMUTH. 

LEAD. 

TIN. 

REMARKS. 

I 

7 

2 

4 

Softens  at  the  boiling-point  of  water. 

2 

8 

2 

6 

Ditto  ;  easy  of  oxidation. 

3 

8 

2 

4 

Ditto  ;  like  butter. 

4 

16 

4 

7 

Softens  still  more. 

5 

9 

2 

4 

"      less. 

6 

7 

16 

8 

5 
3 

7 
4 

Becomes  nearly  liquid  at  boiling-point, 
quite         "                " 

8 

8 

4 

4 

very 

9 

16 

9 

7 

Ditto. 

10 

8 

5 

3 

Melts  at  205°  F.  (95°  C.). 

ii 

8 

6 

2 

Ditto. 

12 

8 

7 

I 

Softens. 

13 

16 

15 

I 

Does  not  melt  at  212°  F.  (100°  C.). 

IQ4  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

The  fusible  metals  of  most  common  use  are  : 

D'Arcet's :  Bismuth,  8  ;  lead,  5  ;  tin,  3  parts. 

Walker's :  Bismuth,  8  ;  tin,  4  ;  lead,  5  parts ;  antimony,  I 
part.  The  metals  should  be  repeatedly  melted  and  poured 
into  drops,  until  they  can  be  well  mixed  previous  to  fusing 
them  together. 

Onion's :  Lead,  3  ;  tin,  2  ;  bismuth,  5  parts.  Melts  at 
197°  Fahr.  (93°  C). 

If,  to  the  latter,  after  removing  it  from  the  fire,  one  part 
of  warm  quicksilver  be  added,  it  will  remain  liquid  at  170° 
Fahr.,  and  become  a  firm  solid  only  at  140°  Fahr.  (77°  C. ; 
60°  C.). 

Another :  Bismuth,  2  ;  lead,  5  ;  tin,  3  parts.  Melts  in 
boiling  water. 

They  are  frequently  used  to  make  toy  spoons,  which  sur- 
prise the  uninitiated  by  melting  in  hot  liquors.  A  little  mer- 
cury may  be  added  to  lower  the  melting  points. 

The  first  two  are  specially  adapted  for  making  electrotype 
moulds.  French  cliche  moulds  are  made  with  the  second 
alloy.  These  alloys  are  also  used  to  form  pencils  for  writing, 
also  as  metal  baths  in  the  laboratory,  or  for  soft  soldering  joints. 

The  committee  of  the  Franklin  Institute,  experimenting 
on  steam  boilers  in  1836,  made  an  examination  on  the  be- 
havior of  the  "  fusible  metals,"  and  reported  : 

That  the  impurities  of  the  commercial  metals,  lead,  tin 
and  bismuth,  do  not  usually  affect  the  melting  points  of 
these  alloys ;  and  that  the  compounds  made  by  alloying 
them  in  chemically  equivalent  proportions  do  not  present 
the  characteristics  of  chemical  compounds.  They  found  that 
alloys  ranging  between  SnPb  and  SnPb6  give  nearly  the 
same  temperatures  of  fusion,  but  differ  in  their  rates  of 
change  from  the  solid,  through  the  plastic  to  the  liquid  state. 
The  temperatures  of  casting  and  rates  of  cooling  do  not 
affect  the  melting  points.  Separation  of  the  metals  could  be 
effected  by  pressure — a  conclusion  confirmed  by  the  later  ex- 
periments of  Weems;  these  alloys,  when  used  in  "safety 
plugs  "  of  steam  boilers,  should  not  be  exposed  to  the  pres- 
sure of  the  steam.  Very  little  change  is  effected  in  the 


THE  KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.       IQ5 


melting  point  of  an  alloy  of  equal  parts  lead  and  tin  by 
adding  tin  ;  its  melting  point  was  found  to  be  a  few  degrees 
lower  than  reported  by  Parkes. 

Parkes  and  Martin  obtain  the  following : 

TABLE  XXV. 

FUSION   OF  ALLOYS   OF  BISMUTH,    TIN   AND   LEAD. 


BISMUTH. 

LEAD. 

TIN. 

TEMPERATURE. 

Parts. 

Parts. 

Parts. 

Fahr. 

Cen. 

8 

5 

3 

202° 

94-44° 

8 

6 

3 

208 

97.78 

8 

8 

3 

226 

107  64 

8 

8 

4 

236 

112.20 

8 

8 

6 

243 

II6.05 

8 

8 

8 

254 

122.  IO 

8 

10 

8 

266 

127.60 

8 

12 

8 

270 

130.90 

8 

16 

8 

300 

147.40 

8 

16 

10 

304 

149.60 

8 

16 

12 

294 

141  .  90 

8 

16 

14 

290 

139.70 

8 

16 

16 

292 

I40.SO 

8 

16 

18 

298 

I44.IO 

8 

16 

20 

304 

147.40 

8 

16 

22 

312 

152.80 

8 

16 

24 

316 

154-00 

8 

18 

24 

312 

152.90 

8 

20 

24 

310 

I5I.90 

8 

22 

24 

308 

I5I.8O 

8 

24 

24 

310 

152.90 

8 

26 

24 

320 

158.40 

8 

28 

24 

330 

163.00 

8 

30 

24 

342 

170.50 

8 

32 

24 

352 

I76.OO 

8 

32 

28 

332 

165  oo 

8 

32 

30 

328 

163.90 

8 

32 

32 

320 

158.40 

8 

32 

34 

318 

157.30 

8 

32 

36 

320 

158.40' 

8 

32 

38 

322 

159.50 

8 

32 

40 

324 

160.60 

The  thermometer  is  observed  to  rise  about  one  degree, 
Fahr.,  at  the  instant  of  solidifying. 

These  alloys  are  especially  valuable  for  baths  used  in 
tempering  steel  articles  of  small  size.  They  give  a  very 
exact  temperature,  which  may  be  adjusted  to  the  purpose 


196  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


intended.  They  are  used  by  placing  the  article  on  the  sur- 
face of  the  unmelted  alloy,  and  gradually  heating  until  fusion 
occurs  and  they  fall  below  the  surface,  at  which  moment  their 
temperature  is  right ;  they  are  then  removed  and  quickly 
cooled  in  water.  It  is  not  easy,  even  if  possible  at  all,  to 
give  as  uniform  a  temperature  by  the  ordinary  processes  of 
heating,  or  to  obtain  the  exact  heat  desired,  and  the  quality 
of  the  tool  is  not  so  easy  of  adjustment  by  any  other  method. 

The  Homberg  alloy  consists  of  equal  parts  of  these 
metals,  and  melts  at  about  254°  F.  (122°  C.)  ;  it  is  silver  white. 
Krafft's  alloy  is  composed  of  bismuth  63,  lead  25,  tin  12; 
it  melts  at  220°  F.  (104°  C.).  Rose's  alloy  is  a  more  common 
one — 40  bismuth,  20  lead,  20  tin,  or  50  bismuth,  20  lead,  30 
tin.  Another,  Rose's  alloy,  is  of  50  bismuth,  25  each  lead 
and  tin,  and  melts  at  205°  F.  (95°  C.).  According  to 
Ermann,  this  alloy  fuses  at  200°  F.  (94°  C.)  and  expands  from 
a  volume  i,at  the  boiling  point  of  water,  to  1.0083  at  114°  F. 
(44°  C.),  contracts  to  0.9913  at  148°  F.  (70°  C.)  and  then  ex- 
pands to  1.0083  at  tne  melting  point. 

Dobereiner's  alloy,  bismuth  46.6,  tin  19.4,  lead  34, 
melts  at  210°  F.  (99°  C.). 

Bismuth,  Lead  and  Zinc  in  equal  parts  form  an  alloy 
which  melts  in  boiling  water,  according  to  Mackensie. 

The  melting  points  of  fusible  alloys,  as  determined  by 
Grehm,  are  as  follows  (see  Art.  120): 


ALLOYS. 

SOFTENS 

MELTS 

Tin. 

Lead. 

atF. 

atC. 

at  F. 

atC. 

2 

2 

365° 

185° 

372° 

189° 

2 

6 

372 

189 

383 

195 

2 

7 

377* 

I9S 

388 

198 

2 

8 

3954 

202 

406  to  410 

216 

118.  Lead  and  Antimony  uniter  eadily  and  in  all  propor- 
tions, forming  alloys  of  intermediate  character,  of  which  the 
most  familiar  is  a  u  type  metal,"  lead  34,  antimony  I.  The 


THE  KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.       197 


proportions  vary  with  the  size  of  type  and  with  the  character 
of  the  work  to  be  done.  The  alloy  is  ductile,  quite  strong, 
hard  enough  to  bear  considerable  use  without  wear  or  defor- 
mation, and  not  so  hard  as  to  injure  the  paper.  It  fuses  at  a  low 
cherry-red  heat,  is  not  easily  oxidized,  and  differs  from  lead 
in  most  of  its  qualities  simply  by  possessing  greater  hardness. 

Keys  of  flutes  and  similar  parts  of  instruments  are  made 
of  lead  2,  antimony  I.  Shot  for  guns  is  often  hardened  with 
antimony,  and  rifle  bullets  for  large  game  are  very  frequently 
similarly  made,  introducing  very  small  quanties  of  either  tin 
or  antimony  or  both.  Low  grade  lead  sold  to  shot-makers 
often  contains  I  or  2  per  cent,  antimony. 

The  alloy  of  lead  with  even  a  very  small  percentage  of 
antimony  has  been  found,  by  Bischoff,  to  be  subject  to  rapid 
corrosion  by  even  very  pure  water.  As  the  salts  of  lead  are 
poisonous,  any  use  of  lead  or  of  its  alloys  under  conditions 
favorable  to  the  formation  of  solutions  liable  to  enter  into 
drinking-water  or  food  must  be  carefully  avoided. 

Riche  reports  the  densities  of  alloys  of  lead  and  antimony 
as  below : 

Density  of  the  antimony 6.641 

Density  of  the  lead 12.364 


THEORETICAL 
DENSITY. 

EXPERIMENTAL 
DENSITY. 

DIFFERENCE. 

REMARKS. 

Sb4  Pb            .      . 

7    2^7 

7   214 

—  .023 

Sb3  Pb  

7.  age 

7  ^61 

—  .024 

Sb,  Pb  

7  6*1 

7.622 

—  .029 

Sb  Pb  

8.271 

8.233 

—  .038 

Sb  Pbi  

9O46 

8.QQQ 

—  .047 

Maximum  dilatation. 

Sb  Pb3  

9    CIQ 

9.  502 

-.008 

Sb  Pb4 

98lO 

Q   8l7 

—  .OO2 

Sb  Pb5  

IO   O4O 

10.040 

Nulle. 

Sb  Pb6 

10  206 

IO   211 

+  .005 

Sb  Pb7 

IO   V\ti 

IO   ^44 

4-  .ooq 

Sb  Pb8  

IO  4^8 

IO-455 

+  .017 

Sb  Pb9 

10  521 

IO   S4I 

+  .020 

SbPbio     .      .      . 

jo  <;o2 

IO.6I5 

-4-  .023 

Maximum  contractioa 

Sb  Pbi  ,  

10.652 

10.673 

+  .021 

Sb  Pb,3 

10  702 

IO.722 

+  .O2O 

Sb  Pb,3  

IO  .  74.6 

10.764 

+  .018 

Sb  Pb,4.      . 

10  785 

IO.SO2 

+  .OI7 

198   MATERIALS  OF  ENGINEERING— NOK-FERROUS  METALS. 

The  maximum  of  contraction  corresponds  to  an  atomic 
alJoy  SbPbIO,  which  has  a  rather  simple  composition,  and 
near  the  alloy  SbPb2  is  found  the  maximum  of  dilatation. 

These  alloys  are  crystalline.  The  alloys  near  SbPb2  crys- 
tallize in  quite  large  scales. 

Up.  Tin  and  Antimony  are  easily  alloyed,  forming  a  sil- 
ver or  tin-white  alloy,  according  to  the  proportion  of  tin, 
usually  brittle,  and  often  sonorous  when  the  antimony  is 
present  in  considerable  amount ;  its  specific  gravity  is  less 
than  the  mean  of  the  two  constituents.  Berzelius  states  that 
the  alloy  of  3  parts  tin  to  I  of  antimony  can  be  worked  hot, 
although  liable  to  crack  along  the  edges.  Berthier  found  the 
alloy,  tin  4,  antimony  I,  very  malleable  and  excellent  for  mak- 
ing hollow  ware  and  for  white-metal  cocks  ;  the  mixture,  tin 
6,  antimony  i,  is  also  used  for  such  purposes  and  also  for 
various  "  pewter "  (so-called)  articles.  This  alloy  takes  a 
good  polish,  which  slowly  disappears  with  long  exposure  to 
the  atmosphere.  For  domestic  utensils  an  alloy  of  these  metals 
is  often  used,  as  free  from  danger  of  injuring  food  cooked  or 
kept  in  them  ;  the  alloy  is  not  usually  affected  by  the  acids 
to  which  it  is  there  exposed. 

Chaudet  investigated  these  alloys  with  considerable  care.* 
He  found  that  containing  equal  parts  of  tin  and  antimony 
harder  than  the  latter,  brittle  and  weak,  and  easily  powdered. 
Its  fracture  was  white  and  fine  grained,  and  its  specific  grav- 
ity 6.8. 

The  alloy  of  tin  3,  antimony  i,  had  a  specific  gravity  of 
7.06,  was  somewhat  malleable  under  the  hammer,  but  very 
liable  to  crack  ;  it  had  much  less  ductility  than  tin. 

Nitric  acid  oxidizes  these  alloys  without  dissolving  them, 
and  the  oxide  dissolves  readily  in  hydrochloric  acid,  from 
which  the  addition  of  water  causes  the  precipitation  of  the 
metals. 

120.  Tin  and  Lead  alloy  freely  in  all  proportions,  and 
the  two  metals  are  often  found  associated  in  nature.  The 
addition  of  lead  hardens  tin,  weakens  it,  alters  its  color  from 

*  "  Alliages  Metalliques." 


THE  KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.       199 

white  to  gray,  and  changes  its  texture.  When  3  parts  tin 
and  I  of  lead  are  used,  the  hardest  and  strongest  alloy  is 
produced ;  its  density  is  8.  An  alloy  of  tin  I,  lead  2,  is  used 
for  a  lead-solder  and  known  as  plumber's  solder,  and  the 
proportions  are  variable  up  to  equal  parts  of  each ;  its  density 
is  9.4  to  9.6.  Tin  2  or  3,  lead  I,  produce  alloys  which  are 
very  fusible,  harder  than  either  lead  or  tin,  and  which  are 
used  as  tinner's  solders ;  fluxed  with  resin,  they  are  found 
valuable  in  joining  all  kinds  of  tin-smith's  work;  the  propor- 
tion of  the  constituents  is  sometimes  I  to  I,  and  these  alloys 
are  known  as  "  soft-solder." 

According  to  Watson  the  densities  of  these  alloys  are  as 
follows : 

TIN.  LEAD.  S.  G. 


O 
10 

32 

16 
8 
4 

2 
I 


"•3 

7.2 

7-3 
7-4 
7-6 

7-8 
8.2 
8.8 


These  alloys  have  a  large  number  of  applications  in  the 
arts  in  making  small  instruments,  apparatus  and  utensils ; 
they  are  used  in  plating  copper,  in  making  organ-pipes,  and 
formerly  in  domestic  utensils— for  which,  however,  they  are 
unfitted  by  the  solubility  and  the  poisonous  properties  of  the 
lead,  which  are,  however,  greatly  reduced  by  the  presence  of 
the  tin.  The  alloy  containing  16  to  18  per  cent,  lead  is  not 
sensibly  attacked  by  vinegar  or  fruit  acids.  Alloys  used  in 
plating  copper  contain  from  40  to  50  per  cent.  lead.  Of  the 
alloys  of  these  two  metals,  that  containing  little  or  no  ob- 
servable amount  of  lead  is  used  for  domestic  utensils ;  8  per 
cent,  lead  gives  a  useful  alloy  for  other  dishes ;  20  per  cent, 
lead  gives  an  alloy  in  considerable  demand  for  ornamental 
castings. 

Messrs.  Parkes  and  Martin  have  determined  and  tabu- 
lated the  melting  points  of  these  alloys,  as  in  the  following 
table : 


200  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE   XXVI. 

MELTING   POINTS    OF   TIN-LEAD   ALLOYS. 


PROPORTIONS. 

MELTING  POINTS. 

PROPORTIONS. 

MELTING  POINTS. 

Tin. 

Lead. 

Fahr. 

Cent. 

Tin. 

Lead. 

Fahr. 

Cent. 

4 

4 

372° 

187° 

4 

28 

527° 

271° 

6 

4 

336 

167 

4 

30 

530 

274 

8 

4 

340 

169 

4 

32 

532 

275 

10 

4 

348 

174 

4 

34 

535 

277 

12 

4 

336 

178 

4 

3i 

538 

278 

14 

4 

362 

182 

4 

38 

540 

279 

16 

4 

367 

184 

4 

40 

542 

281 

18 

4 

372 

188 

4 

42  . 

544 

282 

20 

4 

378 

190 

4 

44 

546 

283 

22 

4 

380 

191 

4 

46 

548 

284 

24 

4 

382 

193 

4 

48 

550 

285 

4 

4 

372 

187 

4 

5o 

55i 

285 

4 

6 

412 

209 

4 

52 

552 

286 

4 

8 

442 

225 

4 

54 

554 

287 

4 

10 

470 

241 

4 

56 

555 

288 

4 

12 

482 

248 

4 

58 

556 

288 

4 

14 

49° 

258 

4 

60 

557 

289 

4 

16 

498 

256 

4 

62 

557 

289 

4 

18 

505 

260 

4 

64 

557 

289 

4 

20 

512 

264 

4 

66 

557 

289 

4 

22 

517 

267 

4 

68 

557 

289 

4 

24 

519 

268 

4 

70 

558 

289 

4 

26 

523 

270 

Parkes  and  Martin  propose  the  following  alloys  for  baths 
used  by  cutlers  and   others  in  tempering  and  heating  steel 

articles : 

TABLE  XXVII. 


BATHS   FOR  TEMPERING. 


NO. 

USE. 

LEAD. 

TIN. 

MELTING  POINTS. 

F. 

c. 

I 
2 

3 
4 

6 

8 
9 

10 

II 

12 

7 
74 
8 
81 

10 

14 
19 
30 
48 
50 
Oilb« 

j 

4 
4 
4 
4 
4 
4 
4 
4 
4 
4 
riling. 

4 

420° 
430 
442 
450 
470 
490 
509 
530 
550 
558 
600 
612 

213° 

221 
226 
232 
241 

252 
262 
274 
285 
289 
312 
319 

Other  surgical  instruments.  .  .  . 
Razors  

Pen-knives 

Knives,  scalpels  etc 

Chisels,  garden  knives   

Hatches 

Table  knives  

Swords,  watch-springs   

Large  springs,  small  saws  
Hand  saws   

Articles  of  low  temper 

THE  KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.       2OI 


Tin  and  lead  in  equal  parts  make  an  alloy  used  for  organ 
pipes.  It  is  cast  in  sheets  on  a  table ;  these  sheets  are 
beaten  smooth  with  a  "  planer,"  trimmed  to  size,  rolled  into 
shape  and  soldered  together  at  the  abutting  edges. 

121.  Tin  and  Zinc  unite,  in  all  proportions,  readily  and 
uniformly,  the  quality  varying  less  with  variation  of  propor- 
tions than  in  alloys  generally,  as  may  be  seen  by  studying 
the  change  of  strength  exhibited  by  the  map  and  model 
shown  in  the  chapter  on  the  ternary  alloys.  The  introduction 
of  zinc  increases  the  hardness  of  tin,  and  rather  increases  its 
whiteness,  when  in  small  proportion  ;  in  larger  quantities  it 
reduces  ductility  perceptibly.  The  alloy  is  of  granular,  some- 
times crystalline,  structure,  as  revealed  by  fracture,  and  is 
somewhat  sonorous.  With  equal  parts  tin  and  zinc  the  alloy 
is  rather  hard,  moderately  ductile,  and  of  a  very  brilliant 
lustre. 

According  to  Koechl,  the  following  are  melting-points  of 
these  alloys : 

TABLE  XXVIII. 

FUSION   OF  TIN-ZINC   ALLOYS. 


TIN 

ZINC 

TEMPERATURE    OF    FUSION. 

Deg.  Fahr. 

Deg.  Cent. 

I 

3 

500-572 

260-300 

Pure  metals. 

2 

4 

572-662 

300-350 

"          " 

3 

2 

428-680 

220-360 

«          « 

i 

I 

472-662 

250-350 

Commercial. 

i 

I 

680-932 

460-500 

Pure  metals. 

The  alloy  of  equal  parts  of  tin  and  zinc  is  said  by  some 
authorities  to  be  nearly  as  strong  as  brass,  to  be  much  cheaper, 
and  a  better  anti-friction  metal ;  but  it  is  necessary  that  the 
zinc  should  be  very  pure.  This  alloy  has  been  used  in  the 
form  of  roofing  sheets.  The  alloy  tin  75,  zinc  25,  makes  ex- 
cellent metal  patterns,  the  alloy  flowing  freely,  running  "  sharp" 
and  expanding  slightly  when  solidifying  ;  it  should  not  be 
overheated,  and  should  be  constantly  stirred  while  pouring, 


2O2  MA  TERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

to  insure  uniformity.     This  metal  works  easily,  turns  well  in 
the  lathe,  and  does  not  clog  the  file. 

122.  Antimony,  Bismuth,  and  Lead  unite  to  form  an  alloy 
which  expands  on  cooling,  and  which  is  therefore  used  for 
type-metal.     Mackensie's  alloy  is  antimony  16,  bismuth  16, 
lead  68.     Stereotype  plates  of  good  quality  may  be  made  of 
this  composition. 

123.  Antimony,  Tin,  and  Lead  are  alloyed  in  the  pro- 
portion of  antimony  17,  tin  13,  lead  70,  to  form  another  Mac- 
kensie  metal  for  stereotype  plates  and  other  printers'  work. 
Sheets  of  this,  or  a  similar  alloy,  are  used  in  engraving  music 
for  printing  ;  a  composition  reported  by  Berthier  is  antimony 
5,  tin  60,  lead  35. 

124.  Antimony,  Tin,  and  Zinc,  in  the  proportions  anti- 
mony 12,  tin  44,  zinc  44,  make  an  alloy  considered  excellent 
for  lining  pump-barrels. 

125.  Antimony,  Bismuth,  Tin,  and  Lead,  in  the  propor- 
tions tin  76,  bismuth  8,  antimony  8,  lead  8,  form  the  "  Queen's 
Metal,"  which  is  one  of  the  "  pewter  "  alloys  of  greatest  beauty 
and  durability. 

126.  Pewter  and  Britannia  Metal.—  Pewter  has  a  wide 
range  of  composition,  from  tin  20,  copper  I,  to  tin  2,  copper 
i.   The  alloy  is  often  mixed  with  lead,  of  which  the  Pewterers* 
Company  in  1772*  permitted  enough  to  bring  the  density  of 
the  pewter  from  fff  \  to  |||f  that  of  tin.    The  best  Britannia, 
a  metal  of  this  class,  is  said  to  be  tin  77,  antimony  15,  copper 
7,  zinc  2  ;  the  alloy  is  cast  in  flat  ingots  and  rolled  into  sheets. 

Britannia  wares,  made  in  Sheffield,  are  often  composed  of 
$y2  parts  block  tin,  28  parts  antimony,  8  of  copper,  and  8  of 
brass.  The  tin  is  melted  and  kept  at  a  red  heat  while  the 
antimony,  the  copper,  and  the  brass  are  successively  added, 
molten.  The  liquid  alloy  is  ladled  into  the  ingot  moulds, 
which  are  slab-shaped  cast-iron  boxes,  and  the  slabs  thus 
made  are  subsequently  rolled  into  sheets  or  recast  into  the 
form  desired,  or  into  such  shapes  as  may  be  easily  modified 
to  the  necessary  extent.  Spherical  vessels  are  usually  "  spun 
up  "  in  halves,  which  are  then  united  by  soldering.  The 

*  British  Industries.     Bevan,  1871. 


THE  KALCHOIDS  AND  MISCELLANEOUS  ALLOYS.       203 

solder  is  any  very  fusible  composition  of  this  class,  and  is  often 
made  of  tin  75,  lead  25.  The  fusibility  of  the  metal  is  such 
that  it  requires  some  dexterity  and  great  care  to  prevent  its 
injury  in  the  process  of  soldering.  Britannia  is  easily  shaped 
by  all  the  familiar  processes  ;  it  may  be  cast,  rolled  and  ham- 
mered, and  cut  in  the  lathe  or  by  hand  tools  with  equal 
facility. 

127.  Iron  and  Manganese  have  a  strong  affinity.     In 
small  proportions  manganese  confers  whiteness  upon  iron, 
and  the  alloy  called  "  ferro-manganese  "  is  considerably  used 
in  making  steels  containing  very  little  carbon ;  the  carbide  of 
this  alloy,  known  as  "  spiegeleisen,"  or  simply  "  spiegel  "  in 
the   trade,  is   used  in  carburetting   iron   to   produce   steels 
"  higher  "  in  carbon. 

A  small  proportion  of  manganese  renders  iron  less  fusible, 
and  is  said  to  increase  its  tenacity.  Many  of  the  ingot-irons 
in  the  market,  called  "  mild  "  or  "  low  "  steels,  contain  more 
manganese  than  carbon  and  are  very  strong  and  ductile,  and 
make  excellent  material  for  use  where  great  changes  of  tem- 
perature are  not  met  ;  this  alloy  is  not  considered  suitable 
for  springs,  however.  In  large  doses,  manganese  does  not  re- 
duce the  ductility  and  malleability  of  iron  to  the  extent  ob- 
served with  the  introduction  of  carbon.  Karsten  found  that 
nearly  2  per  cent,  manganese  improved  iron.  Mushet  found 
that  the  alloy  iron  71,  manganese  29,  was  not  magnetic,  and 
concluded  that  the  maximum  attainable  in  iron  was  40  per 
cent,  manganese.  As  the  percentage  of  manganese  increases, 
the  alloy  becomes  whiter,  harder,  more  infusible,  and  more 
brittle  if  the  manganese  is  present  in  considerable  amount ; 
it  is  more  subject  to  oxidation  also. 

128.  Platinum  and  Iridium  alloy  to  form  a  composition, 
according  to  Matthey,*  which  is  homogeneous  and  is  capa- 
ble of  being  forged.     Its  density  is  21.5  when  of  the  com- 
position, platinum  98.5,  indium  12.5  by  mixture,  and  platinum 
90,  iridium   10  by  analysis.     The  density  of  the  iridium  was 
22.38.     The  coefficient  of  expansion  was  from  o°  to  16°  C. 
(32°  to  41°  F.),  0.0000254. 

*  Proc.  Royal  Society,  1878. 


204  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

129.  Spence's  "  Metal "  is  not,  strictly  speaking,  a  metal, 
but  is  a  compound  obtained  by  dissolving  metallic  sulphides 
in  molten  sulphur,*  which  is  fo  and  capable  of  receiving  into 
solution  nearly  all  known  compounds  of  sulphur  and  the  use- 
ful metals.  It  was  discovered  by  J.  B.  Spence  in  the  year 
1879.  The  solution,  on  cooling,  solidifies,  forming  a  homo- 
geneous, tenacious  mass  of  the  specific  gravity  3.37  to  3.7  at 
o°  C.  (32°  F.).  According  to  Dr.  Hodgkinson,  when  finely 
powdered,  it  is  acted  upon  slowly  by  concentrated  HC1  and 
NOaHO  in  the  cold ;  in  large  lumps,  little  or  no  action  takes 
place  ;  the  expansion  coefficient  appears  to  be  small.  The 
fracture  is  not  conchoidal,  but  somewhat  like  that  of  cast 
iron. 

It  is  said  to  be  exceedingly  useful  in  the  laboratory  for 
making  the  air-tight  connections  between  glass  tubes  by 
means  of  caoutchouc,  and  a  water  or  mercury  jacket,  where 
rigidity  is  no  disadvantage  ;  the  fusing  point  is  so  low  that  it 
may  be  run  into  the  outer  tube  on  to  the  caoutchouc,  which 
it  grips  on  cooling,  like  a  vice,  and  makes  it  perfectly  tight. 
It  melts  at  320°  F.  (160°  C.),  expands  on  cooling,  is  claimed 
to  be  capable  of  resisting  well  the  disintegrating  action  of  the 
atmosphere,  is  attacked  by  but  few  acids  and  by  them  but 
slowly,  or  by  alkalies,  and  is  insoluble  in  water,  and  may  re- 
ceive a  high  polish  ;  it  makes  clear,  full  castings,  taking  very 
perfect  impressions  ;  it  is  cheap  and  easily  worked.  It  has 
been  used  as  a  solder  for  gas-pipes,  and  as  a  joint-material  in 
place  of  lead. 

*  Jour.  Society  of  Arts.     London,  1879. 


CHAPTER  VII. 

MANUFACTURE  AND  WORKING  OF  ALLOYS. 

130.  Alloys  of  General  Application ;  Brass  Working.— 

Of  the  alloys  described  in  the  preceding  chapter  but  a  few 
are  employed  by  the  engineer  in  his  professional  work,  and  still 
fewer  are  familiar  and  in  common  use.  Of  all  the  known 
alloys,  the  bronzes  and  the  brasses,  the  coin  alloys  and  a  few 
compounds  of  tin,  lead,  zinc,  antimony  and  bismuth,  only, 
are  so  well  known  as  to  be  properly  classed  among  the  ma- 
terials of  constructive  engineering.  All  the  others  are  of  use 
only  in  a  restricted  range  of  application  and  for  a  few  special 
purposes. 

The  methods  of  preparation  are  practically  the  same  for 
all,  and  the  "  brass  foundry  "  is  usually  resorted  to  in  making 
them  all. 

Brass  work  is  divided  into  several  branches,  which,  accord- 
ing to  Aitken,  are : 

1.  Brass  casting,  or  ordinary  foundry  work; 

2.  Bell  and  cabinet-ware  casting ; 

3.  Pot-metal  and  plumbing  work  ; 

4.  Stamped  brass-work; 

5.  Rolled  brass ;  wire-work;  sheathing; 

6.  Tube  making ; 

7.  Lamp  making; 

8.  Gas  fitting ; 

9.  Naval  brass-founding. 

Several  of  these  lines  of  work  may  often  be  carried  on 
together,  but  it  is  usual  to  combine  those  most  nearly  re- 
lated— as  those  involving  casting,  those  in  which  the  metal 
is  rolled  or  wire-drawn,  stamping,  tube-making  and  brass 
finishing. 


206  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Casting  is  described  at  length  in  Arts.  131-2,  on  the  brass 
foundry. 

Sheet-rolling  is  a  very  important  branch  of  brass-making, 
employing  a  large  number  of  work-people  and  sustaining  a 
host  of  minor  trades. 

The  ingot  brass  for  sheet-brass  rolling  is  cast  in  broad, 
shallow,  iron  ingot-moulds,  or  when  larger  masses  are  to  be 
used,  in  stone  moulds,  cut  out  of  the  solid  block.  They  are  well 
oiled  and  powdered  with  charcoal  before  filling  them. 

The  cast  ingots  of  brass  are  called  "  strips,"  and  are 
rolled,  cold,  by  several  successive  "  passes "  through  heavy 
rolls,  with  occasional  annealing  as  they  become  hardened  by 
the  operation  of  the  rolling-mill.  When  the  surface  of  the 
sheet  is  found  to  be  irregular  and  to  contain  spots  of  im- 
purity, the  hand-scraper,  or  a  scraping  machine,  is  employed 
to  remove  them,  and  thus  to  prevent  liability  to  cracking  and 
raggedness  of  surface  or  edges.  When  rolled  nearly  to 
gauge,  the  sheet  is  "  pickled,"  to  remove  the  oxidized  surface, 
and  is  then  passed  through  the  finishing  rolls,  which  are  finely 
polished  and  give  the  sheet  its  final  finish.  Muntz  metals 
can  be  rolled  hot,  and  therefore  much  more  cheaply  than 
other  brass. 

Wire-drawing  is  conducted  as  in  the  drawing  of  iron  and 
steel  wire  ;  but  the  rods  to  be  drawn  are  cut,  by  a  slitting- 
mill,  from  sheet-brass.  Like  iron  wire,  brass  must  be  occa- 
sionally annealed,  in  passing  from  wire-block  to  wire-block. 

Stamping  in  dies  can  be  practised  with  any  of  the  soft 
and  ductile  brasses,  or  other  alloys.  It  is  by  this  process  that 
a  large  proportion  of  the  cheap  brass  ornaments  are  made,  as 
well  as  many  parts  of  various  utensils,  as  lamps,  door-fixtures 
and  kitchen  utensils.  The  die  on  the  anvil  is  made  of  the 
desired  form,  and  the  metal  is  "struck"  into  it  by  the  blow 
of  a  "  drop-hammer"  carrying  a  companion  die,  the  drop 
falling  from  one  to  five  feet  according  to  weight  and  power. 
Heavy  drops  are  always  worked  by  steam  power.  The 
"  force,"  or  die  carried  by  the  drop,  is  usually  of  soft  metal ; 
the  die  on  the  anvil  is  of  steel.  For  fine  and  small  in- 
tricate work,  several  blows  are  struck.  This  kind  of  work 


MANUFACTURE  AND   WORKING  OF  ALLOYS.  2O? 

does  not  compare  favorably  with  cast  brass,  or  bronze,  in 
clearness  and  fineness  of  lines. 

Brass  Tubes  are  made  by  either  of  several  methods. 
Sheet-brass  is  rolled,  over  a  form,  into  a  tube,  and  the  edges 
soldered  together,  or  they  are  rolled  into  cylindrical  shape 
and  soldered.  For  exact  sizing,  a  mandrel  is  placed  within 
the  tube  and  on  this  it  is  rolled  to  gauge.  Seamless  tubes, 
such  as  are  used  in  steam  boilers  and  elsewhere  under  pres- 
sure, are  made  by  rolling,  or  by  drawing  down  cast  cylinders 
in  a  mill  consisting  of  several  sets  of  steel  rolls. 

Brass-finishing  includes  lacquering,  bronzing,  dipping  and 
burnishing  and  other  methods  of  giving  a  surface  finish, 
described  at  the  end  of  this  chapter. 

131.  The  Brass  Foundry  is  usually  an  adjunct  to  large 
manufacturing  establishments.     It  is  generally  small,  and  the 
moulding  room  and  casting  room  are  in  one.     A  drying  room, 
or  core-oven,  is  conveniently  located  at  the  moulding  room 
side  ;  it  may  be  heated  by  either  steam  or  by  stoves,  the  for- 
mer being  the  better  plan.     A  cleaning  room  and,  beyond  it, 
a    finishing   or  dressing  room,  should  be  attached  to  the  foun- 
dry, and,  for  fine  work,  a  lacquering  room  is  also  required. 

The  "  patterns  "  are  of  wood  or  iron,  as  in  iron  founding, 
or  they  may  be  of  stucco  and  pipe-clay.  Patterns  for  brass 
castings  must  be  larger  than  for  iron,  as  shrinkage  is  one-half 
greater,  i.e.,  T\th  inch  to  the  foot,  or  about  20  cm.  per  metre. 
The  <(  shrink-rule"  used  for  iron  will  not  apply  for  brass-work. 
The  flasks,  and  all  details  of  apparatus,  tools,  and  work  are 
very  similar  to  those  used  in  an  iron  foundry,  and  the  meth- 
ods are  the  same  in  the  main.  Castings  are  cooled  rapidly, 
often  with  water,  to  soften  and  toughen  them. 

132.  Melting  and  Casting. — In  the  melting  of  the  ma- 
terials in  the  making  of  alloys  in  the  foundry,  two  general 
methods  of  procedure  are  practised  ;  in  the  one,  all  the  con- 
stituents are  fused  at  the  same  time  in  the  same  crucible  or 
melting  pot ;  in  the  other  they  are  fused  one  after  another  in 
a  definite  order,  which  is  determined  by  their  relative  fusibility, 
volatility,  and  liability  to  oxidation,  or  to  absorb  oxygen  and 
other  gases.     The  first  of  these  methods  is,  perhaps,  the  most 


2O8  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

common,  but  the  second  is  by  far  the  better ;  thus  in  making 
the  most  common  ternary  alloys,  those  of  copper,  tin,  and 
zinc,  the  copper  is  best  melted  first,  the  tin  should  be  next 
introduced,  and  the  zinc,  which  is  volatile  and  oxidizable,  is 
added  last.  If  lead  is  to  be  introduced  into  such  an  alloy,  it 
is  found  best  to  put  it  into  the  crucible  last. 

Other  things  being  equal,  the  metals  should  be  added  in 
the  order  of  their  non-volatility  ;  the  next  controlling  quality 
is  infusibility  ;  the  least  fusible  should  generally  be  melted  first. 

The  casting  and  cooling  of  the  alloy  is  hardly  less  a  mat- 
ter of  importance  than  the  methods  of  fusion.  Liquation  is 
very  liable  to  occur  in  certain  cases,  as  in  many  alloys  of  cop- 
per with  tin,  and  to  prevent  it  the  most  prompt  cooling  pos- 
sible is  resorted  to ;  the  use  of  "  chills,"  or  metal  moulds,  is 
sometimes  found  essential  to  success.  In  these  cases,  it  is  not 
advisable  to  pour  the  alloy  "  cold,"  as  liquation  may  have  al- 
ready commenced  ;  they  should  be  poured  hot — "  sharp,"  as 
the  term  is  often  used  in  the  foundry — and  yet  compelled  to 
chill  quickly,  if  possible. 

The  apparatus  of  the  foundry,  in  which  alloys  are  mixed 
and  cast,  consists  of  an  air,  or  wind,  furnace,  sufficiently  large 
to  receive  the  crucibles  in  which  the  metals  are  melted,  or, 
sometimes,  when  the  masses  handled  are  very  large,  a  rever- 
beratory  "  open  hearth  "  furnace,  which  is  preferably  heated 
with  gas  or  liquid  fuel ;  of  a  collection  of  crucibles,  which  may 
be  iron  melting-pots  for  lead  and  alloys  which  melt  at  a  low 
heat  and  have  no  affinity  for  iron,  but  which  are  usually  of 
clay,  of  graphite,  or  of  graphite  mixed  with  clay  ;  and  utensils 
for  weighing  and  handling  the  metals,  fuels,  and  crucibles.  In 
some  cases  platinum  and  silver  crucibles  are  used,  as  in  lab- 
oratory work,  but  these  are  rarely  needed.  The  crucibles 
should  be  carefully  selected,  since  the  cost  of  these  vessels  is 
often  an  important  item  of  the  expense  account. 

In  melting,  the  constituents  of  the  charge  being  intro- 
duced in  the  order  decided  to  be,  on  the  whole,  best,  the 
liquid  metal  should  be  carefully  stirred  after  each  addition, 
and  in  such  a  manner  as  to  secure  most  complete  intermixture, 
without  liability  to  injure  it  by  exposure  to  an  oxidizing 


MANUFACTURE  AND   WORKING  OF  ALLOYS.  2OQ 

atmosphere.  When  the  alloy  is  not  homogeneous  and  sound, 
it  may  sometimes  be  greatly  improved  by  refusion.  In  mak- 
ing large  castings,  the  several  metals  to  be  alloyed  are  usually 
melted  separately  and  all  finally  poured  together  into  a  reser- 
voir in  which  they  are  thoroughly  mixed  before  "  pouring  the 
casting."  Where  a  reverberatory  furnace  is  used,  the  process 
may  be  conducted  as  in  crucibles  ;  in  this  case,  especial  pre- 
cautions must  be  observed  to  preserve  a  deoxidizing  flame 
within  the  furnace.  WThen  they  are  used  in  making  bronzes, 
great  care  is  taken  to  keep  the  mass  constantly  stirred  to  pre- 
vent liquation  and  the  floating  of  the  tin  to  the  top. 

The  fuel  used  in  the  mint-furnace  is  generally  coke,  which 
should  be  dense,  hard,  bright,  and  should  ring  when  struck. 

In  laige  establishments,  and  especially  in  melting  bronzes, 
the  open-hearth  reverberatory  is  very  generally  used.  Bell 
founders  use  a  peculiar  dome-topped  furnace,  melting  at  more 
moderate  heat. 

In  "  pouring,"  the  small  castings  are  made  first  and  the 
heavier  are  poured  with  the  cooler  metal. 

Sheet-brass  is  first  cast  in  plates  between  heavy  marble 
blocks  washed  with  loam  and  well  dried,  or,  often  in  ingots. 
They  are  rolled  in  heavy  plate-mills  and  occasionally  annealed 
as  they  become  hard  and  unmalleable  in  the  rolls. 

In  making  brass-plates  and  sheet-brass,  the  surface  is 
pickled,  after  the  sheet  is  reduced  nearly  to  size,  in  order  to 
give  it  a  clean  surface,  and  then,  when  a  finish  is  demanded, 
it  is  given  by  a  set  of  polished  rolls. 

Wire-brass  is  cast  and  rolled  into  plates,  which  are  cut 
into  narrow  strips  in  a  "slitting-mill "  by  narrow  interlocking 
roll-collars.  These  strips  are  rolled  to  a  conveniently  small 
size,  and  are  then  sent  to  the  wire-mill  to  be  finished  in  the 
draw-plates. 

133.  Furnace  Manipulation. — In  filling  the  furnaces,  the 
crucibles  are  slowly  heated  to  avoid  danger  of  breaking ;  they 
are  at  first  set  bottom  upward.  When  well  heated,  they  are 
set  mouth  upward  and  charged  with  the  broken  copper.  The 
tin  or  zinc  is  heated  at  the  mouth  of  the  furnace  and  is 
added  gradually  to  the  copper  as  the  latter  becomes  fluid. 
14 


2IO  MATERIALS  OF  ENGINEERING— NON-FERROU S  METALS. 

The  zinc  is  liable  to  volatilization,  and  is,  therefore,  when 
introduced,  plunged  well  below  the  surface  of  the  molten 
copper.  The  Author  has  sometimes  had  it  wrapped  in  dry 
paper  or  other  protecting  material  to  secure  protection  from 
loss  by  volatilization  and  oxidation.  Great  care  is  needed 
to  prevent  the  introduction  of  cold  and  especially  of  damp 
metal ;  seriously  dangerous  explosions  are  sure  to  take  place 
if  this  should  happen. 

The  fumes  arising  from  the  molten  alloys  when  poured 
are  unhealthy,  and  a  form  of  intermittent  fever  known  as  the 
"  brass  ague  "  is  often  produced  by  them  where  proper  pre- 
cautions in  handling  and  in  securing  ventilation  are  not 
observed. 

The  brass-founder's  furnace  consists  of  a  vertical  cast- 
iron  cylinder  or  other  casing — often  a  brick  structure — lined 
with  fire-brick  to  a  diameter  of  10  to  15  inches.  The  flue  is 
led  off  at  one  side  at  the  top,  and  the  whole  is  covered  with  a 
plate  having  an  opening  of  sufficient  size  to  permit  the 
crucible  to  enter  and  fitted  with  a  cover  plate.  The  grate  is 
usually  composed  of  loose  bars  which  can  be  easily  and  in- 
dependently withdrawn  or  inserted. 

Each  furnace  contains  one  crucible,  and  large  castings  are 
only  made  where  several  furnaces  are  in  use  or  where  the 
alloy  can  be  melted  in  a  reverberatory  furnace.  Tuyeres  are 
sometimes  fitted  for  the  purpose  of  increasing  the  rapidity  of 
melting,  and  the  crucibles  are  then,  when  large  castings  are  to 
be  made,  emptied  as  fast  as  ready  into  a  ladle  which  serves 
as  a  collecting  reservoir  from  which  the  mould  is  filled. 

The  fuel  is  usually  either  coke  or  charcoal. 

134.  The  Preparation  of  the  Alloys  involves  considerable 
knowledge  of  the  behavior  of  the  mixture  and  its  constituents 
while  fusing  and  while  the  alloy  is  being  formed,  and  can 
only  be  successful  when  the  skill  and  judgment  of  an  ex- 
perienced founder  aid  in  the  work  of  melting  and  casting. 
There  are  two  methods  of  making  alloys  :  the  one  is  that  of 
weighing  out  the  constituents  in  proper  proportions  and 
mixing  and  melting  all  together;  the  other  is  that  of  mixing 
and  melting  the  constituents  successively  and  in  an  order 


MANUFACTURE  AND  WORKING  OF  ALLOYS.  211 

dependent  upon  the  character  of  the  metals  and  the  alloy 
made  of  them.  The  first  is  the  usual  method  and  is  the  least 
troublesome  and  expensive ;  but  it  does  not  usually  give  as 
sound,  uniform,  and  strong  castings  of  the  alloy  as  the  second. 
In  the  latter  case,  the  metal  of  highest  melting  point  is 
usually  first  fused  and  the  others  are  added  in  the  order  of 
fusibility  or  volatility.  The  order  of  introduction  into  the 
crucible  or  melting-pot  has  an  appreciable  effect  on  the  quality 
of  the  alloy. 

After  the  alloy  has  been  made  and  poured  into  the  ingot, 
or  other  mould,  it  may  change  in  composition  by  the  process 
of  separation  or  "  liquation,"  to  which  reference  is  elsewhere 
made,  either  by  the  denser  metal  settling  out  or  by  the 
change  due  to  formation  of  other  definite  alloys  of  greater 
stability  at  various  points  in  the  mass,  thus  altering  the  com- 
position of  the  metal  all  around  those  points.  Thus  in  gun- 
metal  (bronze)  the  surface  of  fracture  often  has  a  variegated 
color  due  to  separation  of  the  tin  and  the  production  of  a 
variable  composition  of  alloy.  This  will  be  noted  in  the 
description  of  the  behavior  of  many  alloys  made  by  the 
Author.  It  will  be  seen  that  the  rapid  cooling  secured  by  the 
use  of  metal  moulds  is  the  best  means  of  preventing  this 
liquation.  Slow  cooling,  affording  ample  time  for  the  separa- 
tion and  reconcentration  of  the  constituents,  and  for  the  pro- 
duction of  crystals,  permits,  often,  very  serious  loss  of  quality. 
It  will  be  noted  that  the  best  alloys  are  usually  made  most 
successfully  when  the  molten  metal  is  poured  "  sharp,"  L  e.y 
hot,  and  then  rapidly  cooled  to  the  point  of  solidification. 

The  process  of  liquation  is  sometimes  usefully  applied,  as 
in  the  Pattinson  process  of  separating  the  metals  in  argentif- 
erous galena,  or  in  cupriferous  ores  of  lead. 

The  desired  alloy  is  very  rarely  made  of  its  essential  con« 
stituents  only.  A  simple  binary  alloy  of  copper  and  tin  is, 
for  example,  rarely  made  in  commercial  work.  Lead  is  often 
added  to  give  color,  zinc  to  cheapen  it  or  to  flux  it,  and  some- 
times other  metals  to  give  special  qualities.  Statuary  bronze 
usually  contains  some  lead  and  zinc  to  give  it  its  peculiar 
"patina";  bronze  used  in  "hardware"  and  architectural 


212    MATERIALS  OF  ENGINEERING—NON-FERROUS  METALS. 

work,  in  bearings,  etc.,  contains  lead  to  give  color  and  to  make 
it  wear  well ;  brass  is  hardened  greatly,  and  strengthened,  by 
the  addition  of  one  per  cent,  tin,  or  more,  as  in  the  "  maxi- 
mum alloys  "  discovered  by  the  Author.  In  such  cases,  the 
metal  is  added  in  small  quantity  to  the  mixture,  after  the 
latter  is  in  fusion  and  alloyed. 

135.  Minute  Quantities  of  Alloy  often  greatly  influence 
the  properties  and  quality  of  metals.     Thus,  it  is  stated*  that 
lead  alloyed  with  0.003  per  cent,  of  antimony  turns  percep- 
tibly freer  than  pure  lead  ;  that  an  addition  of  0.007  Per  cent, 
copper  unfit  leads  for  use  in  the  manufacture  of  white  lead  ; 
that  gold  containing  0.05  per  cent,  of  lead  exhibits  greatly 
decreased  ductility  ;  that  copper  containing  0.5  per  cent,  iron 
has  but  40  per  cent,  of  the  conductivity  of  pure  copper. 

Nickel  is  too  brittle  to  work ;  but,  alloyed  with  o.i  per  cent, 
magnesium  or  0.3  per  cent,  phosphorus,  it  can  be  rolled  and 
worked.  Brittle  steel  is  sometimes  made  tough  and  malle- 
able by  alloying  it  with  0.08  per  cent,  manganese  or  magne- 
sium. A  difference  of  o.ooi  per  cent,  in  the  amount  of  phos- 
phorus present  in  the  best  Swedish  irons  can  be  plainly 
observed  by  a  change  of  malleability. 

136.  Art  Castings  in  Bronze  represent  the  most  perfect 
work  known  in  the  department  of  foundry  work.     It  has  been 
practised  from  the  earliest  known  and  even  pre-historic  peri- 
ods, and  the  analyses  of  art  castings  found  in  the  Egyptian 
tombs    and    in    Nineveh    prove    that    the    composition    then 
adopted  was  substantially  that  of  the  statuary  bronze,  and 
that  of  the  art-work  of  to-day.     The  Greeks  began  to  make 
bronzes  several  hundred  years  before  the  Christian  era,  and 
before  the  commencement  of  that  era,  had  attained  great  skill 
in  the  art.     The  statue  of  Apollo,  at  Rhodes,  made  by  the 
pupil  of  Lysippus,  Chares,  330  B.C.,  was   about   100  feet  (30 
metres)  high,  and  after  having  been  shaken  down  by  an  earth- 
quake some  60  years  later,  lay  over  900  years  prostrate,  and 
was  then   carried  away  by  a  Jew  who  purchased  it  from  the 
Saracens,  making  a  load,  as  it  is  said,  for  900  camels.     The 
Chinese    and   Japanese   first   made    use   of   bronze    at    some 

*  Der  Techniker,  1883. 


MANUFACTURE  AND   WORKING  OF  ALLOYS.  213 

unknown  but  very  early  date.  The  art  was  long  lost  in  Europe, 
but  was  revived  in  the  i6th  and  i/th  centuries,  and  now  con- 
stitutes an  exceedingly  important  industry. 

Art  castings  of  large  size  are  moulded  and  cast  precisely 
as  other  brass-founding  is  done;  but  great  precaution  is  taken 
in  the  selection  of  materials,  in  determining  exactly  the  desired 
proportions  and  in  all  the  details  of  foundry  practice  and 
manipulation.  The  usual  mixtures  are  given  elsewhere. 

In  making  statuary,  the  model  is  first  formed,  and  is  then 
lined  cff  by  the  founder  in  sections  in  such  manner  that  each 
will  be  likely  to  be  easily  moulded  and  will  "  draw  "  readily  ; 
plaster  patterns  are  made  of  these  sections  separately,  which 
are  used  in  obtaining  metal  copies,  which  latter  are  finally 
joined  together.  Where  the  piece  is  to  be  cast  whole  also, 
the  mould  must  be  often  made  in  many  parts,  in  order  that 
every  section  of  the  mould  may  be  readily  removed.  In  some 
cases,  an  elastic  mould  is  made  within  which  a  wax  model  is 
formed,  the  latter  being  moulded  in  the  sand  in  the  usual 
manner.  For  such  work,  a  plaster  cast  is  usually  first  made, 
which  is  coated  with  any  oily  or  glutinous  substance  which 
will  not  allow  moisture  to  be  transferred,  and  will  not  permit 
the  adherence  of  the  cope  or  mould,  to  be  formed  over  it.  By 
covering  the  model  with  a  thin  coating  of  wax,  an  outer  mould 
can  be  constructed,  and  the  inner  and  outer  shapes  may  thus 
be  separated  by  a  thin  space  which  represents  that  to  be 
filled  by  the  molten  bronze,  and  determines  the  thickness  of 
the  casting.  This  space  is  often  filled  with  wax  and  the  latter 
is  melted  out  when  the  mould  is  sent  into  the  drying  room  or 
oven.  Properly  made,  the  mould  has  smooth,  perfect  sur- 
faces of  the  exact  form  to  be  reproduced,  and  the  bronze, 
when  removed  from  it,  is  an  exact  reproduction  of  the  model, 
only  requiring  a  small  amount  of  work  to  make  it  marketable. 
If  the  composition  and  the  work  are  what  is  desired,  the  sur- 
face of -.the  casting  is  smooth,  precise  in  form,  sharp  in  out- 
line, and  of  good  color.  Statues  thus  made  acquire,  with  age, 
a  color  or  "patina"  which  distinguishes  all  good  bronzes. 

Statuary  bronze,  and  bronze  for  art- work  generally,  should 
have,  when  newly  cast,  a  fresh,  yellow-red  color,  and  a  fine 


214  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

grain,  should  be  easy  to  work  with  file  or  chisel,  very  fluid 
when  melted,  taking  the  finest  impressions  of  the  mould,  and 
when  exposed  to  the  atmosphere  in  the  finished  casting,  should 
take  the  peculiar  green  patina  characteristic  of  old  bronze 
statuary  of  good  quality.  These  qualities  are  not  usually  ob- 
tained in  so  high  a  degree  in  the  copper-tin  or  copper-zinc 
alloys,  the  common  bronzes  and  brasses,  as  in  alloys  contain- 
ing the  three  metals.  According  to  Guettier,  the  best  of  these 
alloys  are  : 

COPPER.  ZINC.  TIN. 

92  6  2 

85  ii  5 

65  32  3 

It  is  very  usual  to  add  i  or  2  per  cent,  of  lead ;  ancient 
bronzes  contain  as  much  as  6  per  cent.  According  to  Pliny, 
bronze  was  made  by  melting  copper  first,  then  adding  12^ 
per  cent,  of  an  alloy  of  equal  parts  tin  and  lead,  known  as 
plumbum  argentarium. 

137.  Stereotype  Metal,  of  which  a  good  quality  is  made 
of  1 6  parts  antimony,  17  parts  tin,  and  67  parts  lead,  is  worked 
thus: 

The  type  is  brushed  over  with  a  small  quantity  of  black- 
lead  and  oil,  placed  in  a  casting-frame,  and  a  cast  taken  in 
plaster  of  Paris.  This  cast  is  dried  in  a  hot  drying-oven 
until  absolutely  free  from  all  moisture,  and  is  held  in  form, 
meantime,  by  securing  it  to  a  flat  cast-iron  plate.  The  stereo- 
type metal  is  cast  upon  the  matrix  thus  produced,  and  the 
plate  thus  obtained  is  planed  up  to  a  gauge  and  fitted  to  the 
press,  or  mounted  on  wooden  blocks  of  the  right  height  to 
work  in  the  press.  Damaged  type  are  cut  out  and  replaced 
with  perfect  ones. 

A  later  process  is  the  following :  *  A  sheet  of  tissue  paper 
covered  with  printing  paper  is  placed  upon  a  perfectly  smooth 
metal  plate,  and  the  two  sheets  are  pasted  together. 

These  sheets  are  laid  over  the  type,  beaten  into  their  in- 
terstices, covered  with  other  sheets  similarly  beaten  down,  and 

*  Spon. 


MANUFACTURE  AND   WORKING  OF  ALLOYS.  21$ 

this  process  is  continued  until  the  mass  of  paper  forms  a 
matrix  of  satisfactory  thickness  and  strength.  Heavier  paper, 
as  cartridge  paper,  is  used  for  the  last  layers.  This  matrix  is 
dried  carefully  between  surfaces  which  hold  it  in  shape,  is  then 
brushed  over  with  French  chalk  or  black  lead,  and  laid  in  the 
casting  box,  where  the  stereotype  metal  is  cast  over  it  and  a 
plate  thus  made. 

138.  German   Silver   is  made    by    English   founders   of 
small  bells  and  similar  articles  of  copper  57,  zinc  19,  nickel  19, 
lead  3,  tin-plate  2.     The  copper  and  nickel  are  fused  together 
first,  the  zinc  added  after  their  fusion,  and  the  other  metals 
last.     Commercial  zinc  containing  lead  is  rarely  pure  enough 
for  the  finer  grades  of  this  alloy  which  do  not  permit  the  in- 
troduction  of   lead.     It   is  difficult  to  obtain  this  alloy  in 
correct  proportions  and  of  good  quality. 

139.  Babbitt's  "Anti-attrition"  Metal  is  usually  not  cast 
directly  into  the  "  brasses  "  to  be  lined  with  it.     It  is  made 
by  melting  separately  4  parts  copper,  12  Banca  tin,  8  regulus 
of  antimony,  and  adding  12  parts  tin  after  fusion.     The  anti- 
mony is  added  to  the  first  portion  of  tin,  and  the  copper  is 
introduced  after  taking  the  melting-pot  away  from  the  fire, 
and  before  pouring  into  the  mould. 

The  charge  is  kept  from  oxidation  by  a  surface  coating  of 
powdered  charcoal.  The  "  lining  metal "  consists  of  this 
"hardening,"  fused  with  twice  its  weight  of  tin,  thus  making 
3.7  parts  copper,  7.4  parts  antimony  and  88.9  parts  tin. 

The  bearing  to  be  lined  is  cast  with  a  shallow  recess  to 
receive  the  Babbitt  metal.  The  portion  to  be  tinned  is 
washed  with  alcohol  and  powdered  with  sal  ammoniac,  and 
those  surfaces  which  are  not  to  receive  the  lining  metal  are 
to  be  covered  with  a  clay  wash.  It  is  then  warmed  suffi- 
ciently to  volatilize  a  part  of  the  sal  ammoniac,  and  tinned. 
The  lining  is  next  cast  in  between  a  former — which  takes  the 
place  of  the  journal — and  the  bearing. 

Founders  often  prefer  to  melt  the  copper  first  in  a  plum- 
bago crucible,  then  to  dry  the  zinc  carefully  and  immerse  the 
whole  in  the  barely  fluid  copper. 

A    report    of    a    committee    of    the    American    Master 


2 1 6  MA  TERIA LS  OF  ENGINEERING— NON-FERR 0  US  ME  TA L S. 

Mechanics'  Association,  reporting  on  the  use  of  Babbitt  metal, 
state  that  thirty-five  replies  to  their  circular  gave  the  following 
facts  relating  to  the  use  of  Babbitt  metal  :  Four  use  gibs 
with  Babbitt ;  four  use  the  solid  octagon  brass  without 
Babbitt;  seven  use  octagon  with  Babbitt;  seven  use  half- 
round  solid  brasses  without  Babbitt ;  four  use  half  round 
brasses  in  three  pieces  with  Babbitt,  and  one  makes  no  re- 
port of  the  use  of  Babbitt.  All,  with  one  exception,  report 
that  the  Babbitt  metal  should  extend  the  entire  length  of  the 
journal  and  should  be  put  on  in  strips  ^  to  i^  inches 
wide,  at  a  point  between  the  top  and  the  front  and  back 
points  of  the  journal  bearing ;  one  inserts  it  by  drilling  holes 
in  the  brass  and  then  filling  in  with  the  metal.  The  Com- 
mittee have  observed  that,  in  engines  of  from  thirty-two  to 
thirty-five  tons  weight,  the  half-round  brass  does  not  give  as 
good  results  as  in  lighter  engines.  Good  results  may  be  ob- 
tained from  a  hexagon-shaped  brass  if  properly  fitted.  The 
Babbitt  metal  will  wear  until  it  is  cut  through  into  the  cast- 
iron.  The  recess  in  the  top  of  the  brass  is  of  advantage  also 
as  a  reservoir  for  oil ;  and  as  there  is  less  bearing  at  that 
point,  the  brass  wears  away  and  the  shaft  beds  itself  into  the 
brass,  so  that  there  is  no  lost  motion  or  pounding  between 
the  shaft  and  the  brass.  The  Committee  is  of  opinion  that 
the  use  of  Babbitt  metal  is  advisable. 

140.  Solders  are  alloys  used  in  joining  metallic  surfaces, 
and  parts  of  apparatus  or  constructions,  by  fusing  them  upon 
the  surfaces  of  contact,  and  allowing  them  to  cool,  obtaining 
a  more  or  less  firm  and  tenacious  union.  They  have  a  wide 
range  of  composition  ;  the  "  soft  solders  "  are  made  of  tin  and 
lead  ;  "  hard  solders  "  are  usually  made  of  brass  ;  and  special 
solders  are  composed  of  various  alloys  of  copper,  zinc,  lead, 
tin,  bismuth,  gold  and  silver.  Haswell's  table  of  solders  is 
given  later. 

In  soldering  copper,  brass,  or  iron  with  soft  solder,  a 
"  soldering  iron  "  is  used  to  melt,  and  to  apply  the  solder  to 
the  work.  This  instrument  consists  of  a  copper  head,  shaped 
somewhat  like  a  machinist's  hammer,  the  large  end  of  which 
is  inserted  longitudinally  in  the  claw-shaped  end  of  an  iron 


MANUFACTURE  AND   WORKING  OF  ALLOYS. 

holder,  which  is  itself  carried  by  a  wooden  handle ;  it  is 
heated  in  a  small  charcoal-furnace,  or  "  brazier,"  which  is 
especially  constructed  for  the  purpose. 

A  "  soldering  fluid,"  usually  a  solution  of  zinc  in  hydro- 
chloric acid,  is  used  to  remove  the  oxide  from  the  surfaces  to 
be  joined  and  to  give  them  a  coating  of  zinc,  to  which  the 
solder  will  promptly  adhere. 

Soldering  is  often  successfully  performed  by  cleaning  the 
surfaces  thoroughly,  fitting  them  nicely  together  with  a  file, 
if  necessary,  placing  a  piece  of  tin-foil  between  them,  binding 
them  firmly  together  with  "  binding  wire,"  and  heating  in 
the  flame  of  a  lamp  or  a  Bunsen  burner,  or  in  the  fire,  until 
the  tin  melts  and  unites  with  both  surfaces.  Joints  carefully 
made  may  be  united,  in  this  way,  so  neatly  as  to  be  invisible. 
When  using  the  more  fusible  solders,  as  those  containing 
bismuth,  a  fire  is  seldom  needed.  When  one  joint  has  been 
made  with  hard  solder,  it  is  not  always  safe  to  make  another 
near  it  with  the  same  composition  ;  a  softer  soldei;  should 
then  be  used. 

Soft  solders  are  not  malleable,  and  where  this  quality  is 
demanded,  the  solder  is  necessarily  of  the  hard  variety.  An 
excellent  solder  for  such  work  is  made  with  silver  and  brass 
in  equal  parts. 

Coin  silver,  in  thin  sheets,  is  an  excellent  solder  for  cop- 
per, hard  brass,  and  wrought  iron.  Cast  iron  cannot  be  readily 
soldered,  and  the  attempt  is  rarely  made. 

In  making  solders,  great  care  is  to  be  taken  to  secure  uni- 
formity of  composition  ;  they  are  often  granulated  by  pour- 
ing from  the  crucible  or  ladle  through  a  wet  broom  or  from  a 
considerable  height  into  water,  or  they  are  cast  in  ingots 
and  reduced  to  a  powder  by  filing  or  by  machinery.  The  silver 
and  the  gold  solders  are  usually  rolled  into  sheets  ;  the  soft 
solders  are  generally  sold  in  sticks,  as  is  also  pure  tin  ;  those 
which  are  rich  in  tin  are  distinguished  by  their  peculiar  "  tin- 
cry,"  which  is  destroyed  by  a  very  small  admixture  of  other 
metals.  In  making  solders,  as  all  other  such  alloys,  the  most 
infusible  metal  is  first  melted,  and  the  other  constituents  are 
added  in  the  order  of  infusibility. 


OF  THE 

UNIVERSITY 


218  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

fusible  and  are  melted  under  tallow,  and  the  hard  solders  are 
prepared  under  a  covering  of  powdered  charcoal  to  prevent 
oxidation. 

Yellow  brass,  containing  from  65  to  80  per  cent,  copper, 
will  be  found  useful  at  times  in  brazing  wrought  iron,  mild 
steel,  and  all  the  common  brasses  and  bronzes  containing  less 
than  10  per  cent,  tin  or  lead.  Equal  parts  of  copper  and  zinc 
make  a  good  solder  for  yellow  brass  and  is  known  as  "  broom  " 
solder.  Tin  and  lead  are  sometimes  added,  but  probably 
without  advantage,  the  one  making  the  solder  hard,  the  other 
weakening  it.  For  brazing  iron,  yellow  brass  is  excellent. 

In  using  these  solders,  the  surfaces  to  be  brazed  should 
be  well  cleansed,  sprinkled  with  borax,  and  bound  tightly  to- 
gether with  fine  iron  wire.  A  clay  "  dam  "  around  the  joint 
is  useful  in  confining  the  solder  in  place  when  melting.  The 
heating  should  be  gradual  and  the  temperature  brought  slowly 
up  to  a  red  heat,  occasionally  adding  borax,  and,  finally,  the 
heat  should  be  more  quickly  raised  until  the  solder  melts  and 
fumes,  when  the  piece  is  cooled. 

Silver  and  yellow  brass  make  good  solders  for  steel,  melting 
at  a  moderately  high  heat  and  having  considerable  strength. 
Both  solder  and  flux  should  be  used  sparingly  to  secure  good 
work.  Cast  iron  and  alloys  containing  either  tin  or  lead  in 
considerable  quantities  cannot  be  easily  soldered. 

The  soldering  fluid  answers  as  a  flux  for  soft  solders ;  borax 
is  used  with  the  hard  varieties,  as  it  dissolves  the  oxides  of 
all  metals  thus  treated,  and  leaves  the  clean  metallic  surface 
which  is  essential  to  perfect  union.  Sal  ammoniac  is  often 
added  to  the  soldering  fluid  when  soft  solders  are  used,  and 
resin  is  a  common,  and  in  some  respects  the  best,  flux  for  tin- 
ner's work. 

Platinum  is  soldered  with  gold,  and  German  silver  with  a 
solder  of  equal  parts  of  silver,  brass,  and  zinc. 

The  essentials  of  a  good  solder  are  that  it  shall  have  an  affin- 
ity for  the  metals  to  be  united,  should  melt  at  a  considerably 
lower  temperature,  should  be  strong,  tough,  uniform  in  com- 
position, and  not  readily  oxidized.  (See  tables,  pp.  221,  241.) 

141.  Standard   Compositions  are  often  adopted  by  en- 


MANUFACTURE  AND   WORKING  OF  ALLOYS. 


219 


gineers  for  the  various  purposes  to  which  they  apply  the 
alloys.  The  tables  hereafter  presented  are  full  of  examples. 
In  further  illustration,  we  have  the  following  as  the  compo- 
sitions adopted  by  the  Paris,  Lyons,  and  Mediterranean  Rail- 
way of  France : 

TABLE   XXIX. 

STANDARD   ALLOYS. 


i 

ATT  fYV 

PROPORTIONS. 

TTO17O 

A  .L.LU  i  • 

Copper. 

Tin. 

Zinc. 

Lead. 

Ant. 

U  bc*o* 

Gun-  metal,    i. 

82 

16 

2 

Bearings  . 

2. 

84 

U 

2 

.  . 

Valves,  Screws,  etc. 

3- 

90 

8 

2 

m 

Cocks,  Whistles,  etc. 

Brass,             i. 

70 

30 

.  . 

Tubes. 

2. 

67 

33 

Stuffing-boxes,  etc. 

3- 

65 

35 

.  . 

Handles,  Latches. 

4- 

63 

37 

. 

Plates,  Washers. 

White  metal. 

5 

71 

24 

Bearings. 

Packing  " 

14 

76 

10 

Stuffing-boxes. 

Solder. 

»» 

45 

55 

For  tin  plate. 

40 

60 

•  •'  ; 

'    zinc     ' 

The  useful  alloys  are,  as  already  seen,  exceedingly 
numerous,  and  are  of  extraordinary  variety  in  appearance  and 
physical  qualities.  They  are  applied  to  an  almost  equally 
wide  range  of  uses.  The  following  very  complete  lists  will 
give  an  idea  of  their  number,  quality  and  applications.* 

*  Chas.  Haswell;  Pocket-book,  1882.  C.  Bischoff :  Das  Kupfer  und  seine 
Legi  run  gen  ;  Berlin,  1865.  P.  A.  Bolley:  Recherches  Chimiques  ;  Paris,  1869. 
A.  Herve:  Alliages  Metalliques,  Manuel- Roret ;  Paris,  N.D. 


220   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE  XXX. 

ALLOYS   AND    COMPOSITIONS. — HASWELL. 


.« 

COPPER. 

u 

2 

N 

Z 

P 

NICKEL. 

LEAD. 

ANTIMONY. 

BISMUTH. 

SILVER. 

COBALT  OF 
IRON. 

1 

[  ARSENIC. 

Argentan  

55- 

24. 

21. 

Babbitt's  metal 

3-7 
84.3 
75- 
79  3 
92.2 
80 

5.2 
25- 
6.4 

89. 
10.5 

7-3 

Brass,  common  

hard  
"      mathematical  instruments. 
"      Pinchbeck 

14-3 
7  8 

2O. 

"      red  tombac  
rolled 

88.8 
74-3 
50. 
88.9 

II  .  2 

22    3 

^ 

3-4 
'8.3 

"      tutena°r 

IQ. 

"      very  tenacious  

"      white                                          TO 

80 

IO 

"      wire  

67- 
66. 

33- 
34- 

"      yellow   fine. 

Britannia  metal 

tl          when  fused  add... 

25- 

25- 

Bronze  red                                         '  87 

"         red                                           8^ 

"         yellow 

67.2 
80 

31.2 

1.6 

u         cymbals 

1         gun  metal,  large  
small 

90. 

93- 

7- 

1.4 

'         statuary 

i-7 

Ch  nese  silver 

gc    T 

o    ,8 

Chinese  white  copper  
Church  bells 

40.4 

80. 
69. 

25-4 

5-6 

2.6 
10.  I 

%:5 

,r   6 

'  | 

4-3 

Clock  bells    .. 

1-5 

Clocks,  musical  bells  

*,  - 

12.  5 

German  silver  

33-3 

33-4 

33-3 
31-6 

o  6 

"          fine  

24 

2.5 

Gon-o's             

8?.  6 

18.4 

23. 

20. 

House  bells 

Lathe  bushes  
Machinery  bearings 

80. 
87.5 

hard  

15.6 

Metal  that  expands  in  cooling  
Muntz  metal  

75- 

16.7 

8-3 

60 

Pewter,  best  

86. 
80 

20 

14. 

.... 

Printing  characters  
Sheathing  metal  .  . 

cV 

80. 

20. 

Speculum       " 

66. 
S°. 
66.6 

12. 

Telescopic  mirrors. 

21. 

29. 
33-4 
66.6 

28:4 

4  .4 

(  Mag 
)  Sal-a 

nesia.. 
mmon 

69!' 

•  •  •  4 
iac  2 

.4 

•5 

•'•• 

Temper*  

iS.S 

3reai 
Juicl 

n  of 
clime 

tarta 

r6.'s 
•1-3 

Type  and  stereotype  plates  
"           hard  

7-4 
69.8 

73- 

7-4 
25-8 

12.3 

Oreide  

For  adding  small  quantities  of  copper. 


MANUFACTURE  AND  WORKING  OF  ALLOYS. 
TABLE  XXX.— Continued. 

SOLDERS. 


221 


COPPER. 

2 

H 

LEAD. 

u 
2 

SILVER. 

BISMUTH. 

j 

CALCIMINE. 

ANTIMONY. 

Tin 

2S 

ye 

58 

ifi 

-6 

IO 

"    coarse,  melts  at  500° 

~V\ 

67 

"    ordinary,  melts  at  360°  

67 

33 

Spelter,  soft  

50 

5° 

14        hard.  . 

67 

, 

Lead 

67 

Steel  

13 

82 

Brass  or  copper.  . 

5° 

Fine  brass  r* 

£ 

Gold 

80 

li    hard  

66 

*  • 

"    soft. 

66 

80 

Silver    hard 

67 

*  * 

"       soft  

21 

Pewter 

Iron 

66 

*  " 

*  " 

Copper  

FUSIBLE   COMPOUNDS. 


COMPOUNDS.                                         ZINC. 

TIN. 

LEAD. 

BISMUTH. 

CADMIUM. 

...               j 

25 

*9 
12 

25 

33-3 
3i 

25 

50 

33  4 

So 
50 

I 

Fusing  at  less  than  200°  33.3 
Newton's  fusing  at  less  than  212°  
Fusing  at  150°  to  160°  j     .... 

142.  Special  Recipes. — The  best  bronze  compositions  for 
use  in  engineering  are,  according  to  Guettier,*  the  following : 
For  pumps,  bolts  and  similar  pieces : 


Copper. 
Tin.. 


Copper 90 

Tin.. 


10 


100 


100 


The  latter  is  the  softer  of  the  two.     Often   from  one  to 
four  per  cent,  of  zinc  is  added,  as  already  stated. 


*  Guide  Pratique  ;  Paris,  1865. 


222   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
For  eccentric-straps  and  connecting-rod  bearings : 

Copper 83  84  83  84  82  85.25 

Tin 15  14  15  14  16  12.75 

Zinc 2  2               1.5           1.5  2  2 

Lead ..                0.5           0.5  ..               


100    100     100.0   100.0  100     100.00 

The  addition  of  lead  and  increase  of  copper  gives  softer 
alloys.     Lead  is  often  used  more  freely  than  above. 

Locomotive  driving-axle  bearings : 

Copper 74                80                 85.25  86                  89 

Tin 9.5             18                 12.75  J4                    8 

Zinc , 9.5               2                   2.00  ..                     3 

Lead 7  ..  


100.  o          100              100.00             100  loo 
The  Author  prefers  gun-bronze  to  either  of  the  above. 
For  Locomotive  Slide  Valves-*— 

Copper   phosphate 3.50 

Copper 77.85 

Tin n.oo 

Zinc 7.65 


100.00 

Connecting-Rod  Brasses — 

Copper  phosphate 3.5 

Copper 74. 5 

Tin ii. o 

Zinc .  ii. o 


100. 0 

Axle-boxes — 

No.   i.  No.  2. 

Copper   phosphate 2.5  1.5 

Copper 72. 5  73-5 

Tin 8.0  8.0 

Zinc 17.0  19.0 

IOO.O  IOO.O 


MANUFACTURE  AND   WORKING  OF  ALLOYS.  22$ 

Parts  demanding  greater  strength — 

Copper  phosphate •. 3. 5 

Copper 85.5 

Tin 8.0 

Zinc , 3.0 

100.0 

Zinc  is  here  added  to  the  bronze  to  aid  in  securing  that 
homogeneousness  which  is  essentially  the  result  of  the  ad- 
dition of  phosphorus. 

For  pistons  (rarely  needed) :  copper,  89.75  ;  tin,  2.25  ; 
zinc,  8. 

For  car  and  locomotive  axle  bearings : 

Copper 80  79  86  89 

Tin 18  18  14     2.5 

Zinc 2       2.5  ..     8.5 

Lead o.  5 


IOO  IOO.O  IOO  IOO.O 

For  ordinary  stationary  machine  journal-bearings :  copper, 
82  ;   tin,  1 8. 

For  whistles  of  locomotives  and  bells : 

Copper 80    81     78        79    78        71 

Tin 18    17    20       23     22       26 

Antimony 222        Zinc     6  ..        Zinc     1.8 

Iron     1.2 

IOO     IOO     IOO         IOO     IOO         IOO.O 

The  last  is  the  alloy  of  the  famous  "  silver-bell "  of  Rouen. 
For  pump-buckets,  valves  and  cocks : 

Copper 88  88  86.8 

Tin 10  10  12.4 

Zinc 1.75  2  0.8 

Lead 0.25  .. 


IOO.OO       IOO  IOO.O 


For  hammers  (for  use  on  finished  work)  :  copper,  98  ;  tin,  2. 
This  alloy  will  forge  like  copper;  it  may  be  hardened  by 
adding  more  tin. 


224  MATERIALS  OF  ENGINEERING-NON-FERROVS  METALS. 
For  wagon  axle  bearings : 


Copper. 78 

Tin 20 

Zinc..  2 


Copper.  ...         25 

Cast-iron 70 

Tin 5 


100  100 

The  best  brasses  may  be  taken,  for  general  purposes,  as 
accepted  by  good  makers,  as  follows: 

For  turned  work : 

Copper 61.6  66.5  74.5  79.5 

Zinc 35.3  33.0  25.0  20 

Tin 0.5  0.5  0.5  0.5 

Lead 25               

i  oo.o  100.  o  i  oo.o  100.  o 

The  richer  colors   are  given  by  the  higher  proportions  of 
copper.     The  official  recipe  for  work  in  French  dock-yards  is  : 

Copper 65.80  76.0  85 

Zinc 31.80  24.0  15 

Tin   0.25  .... 

Lead 2.60  0.5  i 


100.45  100.5  IQI 

The  hardest  compositions  are  used  for  the  smallest  pieces. 
These  are  used  in  the  ornamentation  of  engines,  for  brass 
straps,  for  hinges,  and  for  pulley-sheaves. 

Cheap  alloys  for  bearings  have  been  made  of  the  follow- 
ing wide  range  of  composition  : 

Copper 56  5.5  58 

Tin 28  19.5  28 

Zinc 16  80.0  14 

100  1000  100 

The  first — Fenton's  alloy — is  said  to  wear  well,  not  to  be 
specially  liable  to  heating,  and  to  be  very  durable.     The  last 
— MargrafT's  alloy — is  of  similar  quality.     The  second  com- 
position is  much  cheaper  and  lighter,  and  takes  the  place  of 
the  white  alloys  used  in  bearings. 


MANUFACTURE  AND   WORKING  OF  ALLOYS. 

Other  white  metals  for  similar  uses  are : 

Copper 41  91 

Tin 96  50  73  50 

Antimony 8  5  18  5 

108  56  100  56 

The  first  is  used  for  common  bearings;  the  latter  for 
small  bearings  carrying  light  loads.  Still  other  alloys  are : 

Tin ;,„  18.0 

Lead 32  85  4.5 

Zinc 18  .    ..  75.0 

Antimony...., 50  15  2.5 

100  100  100.0 

The  following  are  British  (Woolwich)  official  recipes : 

Copper 20  6  7  8  10 

Tin 2  i  i  i  i 

Zinc i 

23  7  8  9  ii 

which  are  used  as  hard  as  metals  are  desired. 

Kingston's  metal,  formerly  much  used  for  bearings,  is 
made  by  melting  9  parts  copper  with  24  parts  tin,  remelting, 
and  adding  108  parts  tin,  and  finally  9  parts  of  mercury. 

An  alloy  of  90  per  cent,  tin,  8  per  cent,  antimony,  and  2 
per  cent,  copper  has  been  found  excellent  for  crank  and  con- 
necting-rod bearings  on  the  Moscow  and  Nishni  Railroad  of 
Russia.  On  the  Kursk-Charcow-Asovv  Railroad  an  alloy  of 
78.5  per  cent,  tin,  11.5  antimony,  and  10  copper  is  considered 
very  superior  for  pivots  of  all  kinds,  slide  valves,  eccentrics, 
stuffing-boxes,  etc.  The  Swiss  Nordostbahn  Company,  in 
ordering  locomotives  recently,  required  the  following  prepa- 
ration as  a  composition  for  axle  journals:  10  parts  of  anti- 
mony added  to  10  parts  of  melted  copper,  with  80  parts 
of  tin  added,  and  the  alloy  run  into  bars,  to  be  remelted 
for  use. 

Bronze  for  bearings  of  axles,  as  made  for  the  Great  West- 
ern Railway  of  Great  Britain,  has  been  given  the  following 
15 


226  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

composition  :  copper,  22  ;  tin,  67  ;  antimony,  1 1.  French  rail- 
ways have  used  copper,  82;  tin,  18  ;  and  Italian  roads  have 
used  an  alloy  of  tin,  38  ;  antimony,  25  ;  and  lead,  37,  for  a 
lining  metal.  The  Perkins  alloy  for  piston  rings  consists  of 
copper  75,  tin  25,  and  is  used  in  steam  engines  worked  at 
very  high  pressure  without  lubrication. 

143.  A  Classified  Table  of  the  Alloys  has  been  compiled, 
as  follows,  by  Bolley,*  from  the  works  of  BischofT  f  and  other 
authorities,  which  presents  the  most  complete  compendium 
of  the  compositions  used  by  the  engineer  and  in  the  trades, 
known  to  the  Author.  This  table  is  here  given,  omitting  the 
alloys  of  the  "  precious  "  metals. 


TABLE    XXXI. 

CLASSIFIED    LISTS   OF   ALLOYS. 

Alloys  of  Copper. 

BRASS. 
RED  BRASS. 


COPPER. 

ZINC. 

Pinchbeck         .              

en  -6 

6.4 

Q2.  5 

7-  5 

French  Oreide                                        

QO.  O 

IO   O 

«             « 

Vw'" 

8«{.«! 

14  ^ 

82  e./i 

17    J.6 

English      "                   "                        . 

86  38 

13  62 

Halberland  alloy  for  imitation  

87  o 

I^.O 

Mannheim  gold,  0.62  per  cent   tin  and  

8q  AA 

Q.  14 

Tissier's  alloy  for  buttons 

Q7    O 

2   O 

Arsenic    I  .  o 

Tombac   common                                                .  . 

71    ^ 

28.  * 

Arcet  tombac,  gilded  

82    ^ 

17-  7 

Hegermuhle  tombac,  Paris    

85.  q 

14-7 

Red                     "             " 

Q2    O 

*   80 

"                        "         Vienna 

07  8 

2  .2 

Leaf                   "        Ltiden<5cheid  

no   IK 

0.85 

<<                       <«                   « 

vv-  AD 
84.21 

I5.7Q 

Bronze  powder  .... 

81  o 

16.0 

Leaf  bronze  

84.6 

15.4 

"         "         ("  gold  ")  Vienna 

77   Q 

22.  1 

*  Recherches  Chimiques.     Paris,  1869. 

|  Das  Kupfer  und  seine  Legirungen.     Berlin,  1865. 


MANUFACTURE  AND   WORKING  OF  ALLOYS. 
TABLE   XXXI.— Continued. 

YELLOW   BRASS. 


227 


COPPER. 

ZINC. 

Malleable  brass              

70.  1 

2Q    Q 

"             "     Liidenscheid 

72    T\ 

27    27 

Chrysorin                                      

72   O 

28  o 

Cominon  brass  

66  6 

•sa    4 

Bobierre     "     Muntz  metal 

74  62 

oe    08 

"           "     low  grade      .        

en    e 

4O    ^ 

60  o 

og    2 

Iron    I  8 

6s  4 

-^4   6 

"       "      low  grade  

6s  s 

•J2    ^ 

Lead    2  o 

64   2 

•2-3      I 

Lead  and  tin  2  7 

"     ductile  (Storer) 

S-l   O 

46  o 

Mecht's  malleable  brass       

6c    24. 

^4    76 

6O.  26 

7n   74 

<>                     «          i< 

66  o 

^4   O 

Kessler's               "          "          

s8  ^ 

41    7 

Chrysorin   Rauchenberger's  

66.7 

a-i  .  q 

Bristol  brass                                           • 

7<    7 

24    ^ 

it         « 

60  8 

<IQ    2 

6s  q 

•aj.    7 

6l    2S 

J-»-  / 

qg    7C 

'•         "       strong  

•J<7      -J^l 

66  64 

WHITE   METAL. 


COPPER. 

ZINC. 

Bath  alloy  

cc  .O 

AC.     O 

"  Platine  "  

4-1.0 

*>7.O 

Button  alloy  Liidenscheid                       

20  o 

80  o 

Mallett    "      preservative  of  iron   

2C   4 

74.6 

BRONZE-LIKE   BRASS. 

Tombac  Alloys. 


COPPER. 

ZINC. 

TIN. 

80.0 

I7.O 

a.o 

Golden  bronze                               

80  Q7 

9.06 

O  O7 

"       for  ornaments  

"V*  V/ 

82.0 

17.5 

O.  $ 

228   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE    XXXI.— Continued. 
Statuary  Bronze. 


COPPER. 

ZINC. 

£ 

H 

LEAD. 

£ 

0 

& 

NICKEL. 

ANTIMONY. 

The  Shepherd  Potsdam  Palace 

88  68 

I  28 

O77 

I  6l 

7  en 

I   21 

o  18 

Germanicus    Potsdam 

80  78 

20  e 

6  16 

I  ^ 

O.  27 

Augsburg  bronze  

<t     '         « 

89-43 

Q4  74 

O  ^4 

8.17 
1.64 

1.05 
O  24 

0-34 

O.ig 
O.7I 

0.84 

Munich           " 

77  0°, 

IQ  12 

O  QI 

2.20 

O.  12 

0.43 

02  88 

Q     A  A 

4  l8 

2  T.I 

0.  1C, 

Keller's  Louis  XIV 

QI  4O 

5C  -1 

I  70 

I  37 

Henry  IV      Paris 

gq  £,2 

57O 

o  48 

7s  OO 

20  oo 

3OO 

2  OO 

8r»  20 

O  IO 

' 

For  Small  Objects  to  be  Gilded.     Arcet. 

Copper 63 . 7    to  72 . 43 

Zinc 33-55  to  22 . 75 

Tin 2 .50  to    1.87 

Lead ' 0.25  to    2.97 

Leaf  and  Wire  Brass. 


COPPER. 

ZINC. 

TIN. 

LEAD. 

English  wire  

7O.  2Q 

2Q    ?6 

Q    28 

0.  17 

Augsburg  wire 

/*-"  *V 

71    8n 

27    6^ 

o  85 

Jenimapes  leaf     .       ...        . 

64   60 

-IT    7O 

I    4O 

o  20 

Aix  la  Chapelle  leaf  

64.80 

02    8O 

2.OO 

0.40 

White  Alloys  for  Buttons. 


COPPER. 

ZINC. 

TIN. 

LEAD. 

Bristol  Alloy  .... 

e,7   Q 

-36  8 

e    q 

6l  .  12 

^6  ii 

2  .77 

Jackson's  Alloy 

63  88 

OQ    ^ 

e    ce 

63  01 

tje  61 

I    SQ 

'  '  Bidery  " 

48  t;o 

<7-l      -22 

6  06 

12    12 

"Gold"  

eg    71 

-30      Q^ 

e    CQ 

2.  7^ 

MANUFACTURE  AND   WORKING  OF  ALLOYS. 


229 


TABLE    XXXI.— Continued. 
Pewter. 


COPPER. 

ZINC. 

TIN. 

LEAD. 

Berthier's  alloy  

71.  Q 

24.  Q 

1.2 

2.O 

Alloy  to  be  cast  and  worked. 

«                                «t                            4   <               «                    (( 

"               "              gilt...'. 
(                                «                           (I               it                   « 

1        for  clock  work 

64.2 
61.6 
63.7 

64  5 
60.66 

34  6 
35-3 
33-5 
32.4 
^6.88 

O.2 
0.6 

2-5 
02 
I    1*1 

2.0 
2-5 
0-3 
2.9 

O   74. 

4                   «                        t( 

66  06 

a  T  46 

I    4"^ 

o  88 

Bruns,  Oreide,  S.  G.  8.79.  .. 
Oker  brass  (Harz)  

68.21 

64   24 

31-52 

•17   27 

0.48 
O.  SQ 

0.24 

O.I2 

Sheathing  Nails. 
COPPER.  ZINC. 

For  ships 63.60  25.00 

Solder  (Strong). 


TIN. 

2.60 


LEAD. 
8.80 


COPPER. 

ZINC. 

TIN. 

LEAD. 

Yellow,  hard  solder  

£>^.  ^o 

4-1    10 

I    "3O 

O    "3O 

Nearly  white   soft 

44   OO 

4O    QO 

3<i0 

I    20 

\Vhite   very  soft  . 

C7     AA 

27    08 

14    ^8 

ALLOYS    FOR    BEARINGS    AND    CASTINGS. 

Copper-  Tin-Zinc. 


COPPER. 

ZINC. 

TIN. 

Locomotive  and  Railroad  work  : 

85.25 

2.OO 

12-75 

Piston  rings  (Seraino1)                                   .  •  • 

80  oo 

Q.OO 

2.OO 

Axle  bearings  (French)         

82.00 

8.00 

IO.OO 

44           "        hard  (G.  B  )    

87.05 

5.07 

7.88 

44         common  (Fr  ) 

78.00 

2.OO 

2O.OO 

Q7.2O 

2.5O 

"           "         Lafond's  alloys 

8O.OO 

2.OO 

18  oo 

Whistles  (dull)       "           "            

81  oo 

2.OO 

17.00 

82  oo 

2.OO 

16  oo 

Castings  for  pumps,  etc.  ,  Lafond's  alloys  .  . 
Eccentric  straps                                        " 
Stuffing-boxes  (Belgian) 

88.00 
84.00 

QO   2O 

2.OO 
2.00 

6  ^o 

IO.OO 

14.00 

a    CQ 

Pistons  and  rods                            

74   10 

22.20 

•?.  7O 

78    7O 

je    oo 

6    ^O 

Gearing  .                                        ..... 

88  80 

2    7O 

8.^O 

QO.OO 

2.OO 

8.00 

Mathematical  instruments   standards 

82  10 

e  .  10 

12    80 

230  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE    XXXI.— Continued. 


COPPER. 

ZINC. 

TIN. 

ANT. 

LEAD. 

Small   fine  coatings     ....             

7Q.  10 

7.8o 

1-3      JO 

83.70 

Q.  3O 

7.OO 

Medals     .  . 

Q7    OO 

2    OO 

I    OO 

Coins  (Fr.)  

QS  .OO 

1  .OO 

4..OO 

Bronze  to  take  solder  

87.00 

I2.OO 

I    OO 

Steam   whistles 

80  oo 

I&    OO 

2    OO 

Mirrors  

82.74 

8    21 

90-7 

Alloys  of  Copper,  Tin,  Lead  and  Zinc. 


COPPER. 

ZINC. 

TIN. 

LEAD. 

ANT. 

Machinery  brass                     .        . 

71   40 

8.QO 

q.  50 

7.IO 

Bearings  of  engines  

7Q.OO 

5.00 

8.00 

8.00 

Pistons      "        " 

84.00 

8.40 

2.QO 

4   7O 

Parts  at  high  temperature     

QO.  7O 

5  .30 

2.  70 

I.3O 

Golden  colored  

74.OO 

IO.OO 

I.OO 

15.00 

"             "       harder 

70  oo 

IO.OO 

IO.OO 

IO.OO 

83  oo 

I    CO 

15  oo 

o  50 

63    60 

24   60 

2    60 

8  70 

Chinese  white  metal                     . 

72    CO 

14   3O 

4-  7O 

18  co 

Bearings  and  valves,  etc  

80.00 

16.00 

2.OO 

2.OO 

Alloys  Containing  Iron. 


COPPER. 

ZINC. 

TIN. 

LEAD. 

IRON. 

80  oo 

7  80 

2    4O 

o  80 

81    17 

JC,     2O 

14  60 

O   QO 

"            "            durable. 

70    CQ 

9CQ 

Q.  ^O 

7.  en 

O    CO 

Piston-rings  of     "           (Stephenson). 

84.00 

8.30 

2.  go 

4-30 

O.4O 

Alloys  Principally  Copper  and  Tin. 


COPPER. 

TIN. 

ZINC. 

LEAD. 

NICKEL. 

IRON. 

Bell  metal 

78  to  80 

22  to  2O 

«                       4< 

60  oo 

40  oo 

'  '    sonorous 

7C    2O 

24    80 

of  Reichenhall  S  G  8  7 

80  oo 

2O   OO 

metal  white  silvery 

78  oo 

22   OO 

Herbohn 

7C  to  T\ 

2C  to  27 

« 

60  oo 

<3C    oo 

5OO 

« 

71    4"} 

26   40 

2    17 

Darmstadt 

7-5   04 

21    67 

I  .  IQ 

2.  II 

0.  17 

72    C2 

21   06 

2    14 

2.66 

o.  oc. 

MANUFACTURE  AND   WORKING  OF  ALLOYS. 


231 


TABLE   XXXI.— Continued. 
Ordnance  Bronze. 


COPPER. 

TIN. 

Common  gun  metal  

80  **o 

IO.7O 

«            «        « 

OI    7O 

8  ^o 

French  ordnance  

QO    IO 

9QO 

QO.QO 

Q.  IO 

British           "       

OI    74 

8  26 

Mirrors. 


COPPER. 

H 

N 

etf 

1 

SILVER. 

NICKEL. 
LEAD. 

fc 

Composition  Cvu  Sn  .... 

68  21 

3I.7O 

| 

Mudge's  alloy 

68  82 

a  i    18 

Laderig's  alloy  (excellent). 

69.00 

28.70 

Good  lustre  (yellowish)   . 

CQ  OO 

28  60 

21  4O 

i 

Edward's  alloy 

63  30 

32  2O 

I  60 

l.UU 

i 

Cooper's  alloy     

69.  80 
57  80 

25.10 
27  30 

2.60 
3  60 

2.40 

1.  20 

IO.8O 



....  

.... 

Richardson's  alloy  

65.  30 

3O.OO 

O.7O 

2.OO 

2  OO 

Sollit's                 '* 

64  60 

4IO 

Chinese  mirrors  (Eisner)  . 

80  80 

J 

8  40 

Medal  Bronze. 


COPPER. 

TIN. 

QO.  10 

9.QO 

6  50 

"            "    (mean)  

Q2.OO 

8.00 

Machinery  Bronze. 


COPPER. 

TIN. 

08.04. 

1.96 

Eisler's  yellow  bronze  (golden)   hard  and  elastic     .  . 

Q4.  IO 

5QO 

Gearing                       .      .        

01  .  3O 

8  70 

QO.OO 

IO.OO 

Seraing         '*      "         "                  

86  oo 

14   OO 

84.00 

16.00 

Dies  work  well  on  the  bronze                              ... 

ga    ^o 

16  70 

232    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE    XXXI.— Continued. 

GERMAN   SILVER,  ETC. 

Nickel  Alloy. 


COPPER. 

NICKEL. 

United  States  coin 

82  88 

18   15 

Belgian                  "        

7?   OO 

25  oo 

U.  S.  Alloys  in  recent  coinage  : 
First  legal  standard 

gr 

12 

Recent  coinage     .                          

7e 

German  Silver. 


COPPER. 

ZINC. 

NICKEL. 

Common  formula   

55-oo 
50.66 
26  .  30 
43.80 
45.70 

59-30 

55-20 

51.60 
45-70 

52.00 

59-°o 
63.00 
50.00 
50.00 
58-30 
50.00 
55-6o 
60.00 
55-50 
62.50 
50.00 
59-oo 

25.00 

I9-3I 
36.80 
40.60 

39-9° 

25.90 
24.  10 
22.60 

20.00 

26.OO 
3O.OO 
31.00 
31.30 
30.00 
25.00 
25.00 
22.  2O 
20.00 

39  oo 

31.20 
18.80 
30.00 

2O.OO 

13  18 

36.80 
15.60 
17.40 

14.80 
2O.7O 
25.80 
3I-30 

22.OO 
11.00 

6.00 
18.70 
20.00 
16.70 
25.00 

22.20 
20.00 
5-50 
6.30 
31.20 
IO.OO 

Wagner's        "        

Chinese  alloy  (Keferstein) 

"      poor  (Fvfe)  . 

tutenag,  amber-colored,  ha 
Sheffield  alloys  : 
Common  alloy   yellow 

rd  

Silver,  white   

Electrum,  bluish 

Hard  alloy,  can  be  worked  cole 
Berlin  alloys  (Schubarth)  : 
Richest 

1 

Medium  .              ... 

Lowest  

French  alloy  (Arcet) 

'      (Chaval)   

Austrian  a  loy,  table-ware  (Gersdor 

<<                                        <•(                         cc 

"                    malleable          " 
Fricke's              bluish-yellow,  hard 
pale         "         duct 
silvery   hard  

ffl 

le 

harder 

Copper,    Tin,  Nickel. 

COPPER.                      TIN. 

NICKEL. 

For  castings  

52.50                       28.80 
5O.OO                       25.00 

17.70 
25.50 

For  bearings  .  . 

MANUFACTURE  AND   WORKING  OF  ALLOYS. 


233 


TABLE    XXXI.— Continued. 

ALLOYS   LARGELY    GERMAN    SILVER. 


COPPER 

ZINC. 

NICKEL. 

' 

IRON. 

COBALT. 

Chinese  Packfong,  S.  G.  8.432    

4.O.4O 

25.40 

SI  .60 

2    60 

\Vhite  alloy,  hard  and  brittle. 

48  80 

24  40 

J* 

24   4O 

2   40 

CJS.OO 

2*7  .GO 

22   OO 

2   OO 

Parisian  "  Maillechort."  S.  G.,  7.18  ... 
Sheffield  alloy  (Ger.  Silver)  

65.40 

58  20 

13.40 
2C    CQ 

16.80 

I  S    SO 

3-40 
3OO 

.... 

English      "         "         "        

'  '         elastic  .... 

60.00 

*\7   OO 

17.80 

25  oo 

18.80 
1  5  oo 

3-40 
3OO 

ALLOYS   CONTAINING  LITTLE   COPPER. 
Alloys  Rich  in    Tin. 


COPPER. 

TIN. 

ANTIMONY. 

Westphalian  alloy  

7  oo 

82  oo 

II    OO 

Magdeburg-Halberstadt  alloy 

II    OO 

74    OO 

T  J-      QO 

Berlin  alloy     

500 

85  oo 

IO   OO 

Antifriction  alloy  (Karmarsch)  

-I   70 

88  89 

7   41 

<                 «                 « 

6    2^ 

81  25 

12    5O 

«                 «                 « 

976 

7O    T\ 

IO    ^1 

<                 «                 «c 

21    4.4. 

71    41 

7    14 

'                 "      (English) 

97C 

7O    7S 

IO    ^2 

<                       «                  u 

7    80 

76    7O 

JC     eo 

<                       <  t                  « 

2   OO 

72   OO 

26  oo 

Bavarian  alloy      ... 

2    OO 

QO   OO 

8  oo 

Alloys  Rich  in  Zinc. 


COPPER. 

TIN. 

ZINC. 

7.00 

21    OO 

72.OO 

Rolls  for  print-works      

e    OO 

ie    go 

78    SO 

4.2O 

2Q    SO 

66  50 

COPPER. 

TIN. 

ZINC. 

ANTIM. 

Fenton's  antifriction  alloy   

5  ^o 

14.  co 

So.OO 

a               «                 it 
Bearing1  metal  (Manchester)     

5-50 
5.6o 

17  4.7 

So.OO 
76    14 

14.50 

"             "      English   

7  40 

I4.QO 

67.70 

"              "      (Chemnitz)  

5.00 

8.50 

10.00 

234  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE  XXXI.— Continued. 


COPPER. 

Hartshorn's  alloy 8.35 

French  antifriction  alloy  .     25.00 


Alloys  Principally  Iron. 

TIN.  ANTIM.             IRON, 

1.38  1.38                88.89 

5-00  ....                70.00 

Alloy  Largely  Lead. 

COPPER.  LEAD.               ANTIM. 

Bearings  for  railway  work 8.00  80.00             12.00 

Alloy  of  Zinc  and  Lead,  etc. 

COPPER.         TIN.  ZINC.            LEAD. 

Soft  metal 3.00         15.00  40.00        42.00 

Alloy  Principally    Tin  and  Antimony. 

COPPER.  TIN.                ANTIM. 

White  alloy 22.00  33-3Q            44. 50 

BRITANNIA   METAL. 

Alloys  Principally   Tin. 


COPPER. 

TIN. 

ANTIMONY. 

Tournay's  alloy                     

g.  oo 

gi  .00 

For  castings  (Baumgartel)  

i.  80 

Si.go 

16.  30 

L/iidenscheidt  Britannia 

4   OO 

^2  .OO 

24   OO 

Birmingham         "           (sheet)         ... 

I.  'iO 

00.60 

7.8O 

"                    "           (cast)       

o.og 

QO.  71 

g.  20 

Asberry's               " 

2    80 

77   80 

IQ    4O 

ANTIMONY. 

COPPER. 

g 

H 

u 

S3 

N 

BISMUTH. 

LEAD. 

Hard  spelter                        

7    ^O 

I    gO 

go  oo 

Alger's  alloy   white    sonorous  

I.OO 

e  .OO 

Q4.OO 

Beckmann's  blue  bronze 

2    QI 

o  1  6 

Q'J       QT 

Alger's  alloy,  hard,  white,  sonorous. 
White  metal 

2.  IO 
2.40 
O   OO 

97-30 

97.0) 

67    7O 

24    "3O 

0.60 
O.6O 



For  tinning  iron 

e    10 

76    QO 

10  30 

7    7O 

Common  spelter    ... 

A.  4O 

82  qo 

I    ^O 

II.8O 

Pewter  

">  •  7O 

81.20 

1  .60 

II.5O 

Britannia  (Karmarsch) 

6  30 

•2      JO 

go  10 

O    "lO 

"          (Koller) 

10  40 

I    OO 

8=;   70 

2    QO 

Pewter  (leaf)  

7.6o 

1.  80 

8q.  30 

I.  80 

«           «  < 

I    7O 

6.80 

84.  70 

6  80 

MANUFACTURE  AND   WORKING  OF  ALLOYS 
TABLE   XXXI.— Continued. 


235 


COPPER. 

TIN. 

ANTIM. 

ZINC. 

BISMUTH. 

Britannia  (Karmarsch).  .  .  . 
'  '         fine  (Wagner)  .  .  . 
Pewter  often  of  . 

3.60 
0.81 
i  .60 

85.00 
85-64 
Sl.^O 

5-00 

9.66 

6  60 

1.40 

3.06 

6  60 

5-00 
0.83 
I  60 

Alloys  Principally  Zinc. 


i    COPPER. 

1 

TIN. 

ZINC. 

LEAD. 

Hamilton's 

alloy    

<J     CQ 

na   AQ 

3    JO 

"     (loss  3  per  cent. 

Zn)  . 

7.OO 

Q-J      2O 

<!     2O 

Heine's 

« 

J.W 

1  1    J.O 

I    J.O 

8<1    ^O 

2    OO 

"     (loss  3  per  cent. 

Zn)  . 

11.80 

1.50 

83.80 

•*-VT" 
2.90 

IRON. 

1.25 
i.oo 


Alloys  Principally   Tin  and  Zinc. 

COPPER.          TIN.  ZINC. 

No.  i  ....................      2.25        64.00         33-50 

No.  2  ....................      3.00        48.00         4800 

Alloy  Principally  Antimony. 


COPPER.       TIN.  ZINC.      ANTIM. 

White  alloy,  brittle,  for  castings.  .    10.00       20.00         6.00       64.00 


COPPER.     LEAD. 

Best..     4.62         57.80 


Type   Metal. 
ANTIM.  TIN.      NICKEL.     COBALT.     BISMUTH. 

17.34         11.56        4.62         2.90          1.16 


ZINC.  TIN.  LEAD.        COPPER. 

Ehrhardt's 89.00          4.00  3.00  4.00 

"         93.00          3.00          3.00  2.00 


ALLOYS  FREE  FROM  COPPER. 
Tin  and  Zinc. 


Imitation  silver  leaf. . 
Type  metal  (Johnson) 


TIN. 

I. CO 

59 


ZINC. 
II 

33 


230  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

TABLE    XXXI.— Continued. 
Tin  and  Lead. 


TIN. 


LEAD. 


Solder I  i 

' '      weak 2  i 

"       hard  and  strong I  2 

Tin  and  Antimony. 

TIN.  ANTIM. 

Britannia 9  i 

Antifriction  metal  (Karmarsch) 3-7  j 

Type  "       (Johnson) 75  25 

Mercury  and  Tin. 

TIN.        MERCURY. 

Amalgam  for  mirrors 70  30 

'    curved  mirrors 4  i 

* 
Lead  and  Antimony. 

LEAD.      ANTIM. 

Type  metal 16  i 

4  i 

Lead  and  Arsenic. 

LEAD.  ARSENIC. 

Shot  metal 100  0.4-3  •  ° 

Bismuth  and  Mercury. 

BISMUTH.      MERCURY. 

Amalgam  for  glass  globes 80  20 

TRIPLE   ALLOYS. 

Tin,  Lead,  and  Bismuth. 

TIN.  LEAD.          BISMUTH. 

Newton's  fusible  metal 3  5 

Rose's  i  i  2 

Solder 1-4  1-4  i 

Printing  rolls 3  2  I 

Perrotine's  alloy i  r  i 

Antimony,  Lead,  and  Zinc. 

ANTIM.       LEAD.          ZINC. 

Lafond's  allqy  for  bearings 50  30  20 


MANUFACTURE  AND   WORKING  OF  ALLOYS. 

TABLE    XXXI.— Continued. 

Tin,  Zinc,  and  Mercury. 

TIN.  ZINC.    MERCURY. 

Kienmeyer's  electrical  amalgam I  I             2 

Singer's                "             "•         I  2         3-5-6 

OTHER   ALLOYS. 

Tin,  Lead,  Bismuth,  and  Mercury. 

TIN.         LEAD.  BIS.  MER. 

Amalgam  for  curved  mirrors I  I  I  9 

"  "    anatomical  preparations.         7  4  12  20 

Tin,  Lead,  Bismuth,  and  Antimony. 

TIN.         LEAD.        BIS.     ANTIM. 

Queen's  alloy 9  i  i  i 

Perrotine's  alloy  for  rolls ......  48  32 . 5         9  10.5 

144.  Bronzing  is  the  process  of  staining  or  otherwise 
coloring  the  surface  of  brass,  in  imitation  of  bronze — usually 
imitating  old  bronze.  The  methods  of  bronzing  and  the 
bronzing  liquids  are  different  for  different  purposes  and  as 
practised  in  different  localities  and  different  trades.  Brass  is 
very  seriously  subject  to  oxidation,  and  when  polished  soon 
loses  its  brightness  and  its  color.  Polished  surfaces  are  often 
protected  by  the  process  of  lacquering  (to  be  presently  de- 
scribed), but  the  permanent  preservation  of  the  polish  is  rarely 
possible  and  a  coloring  or  bronzing  is  very  commonly  resorted 
to.  It  was  formerly  customary  to  give  scientific  apparatus  a 
fine  polish  and  to  cover  this  surface  with  lacquer ;  it  is  now 
becoming  more  generally  customary  to  bronze  them  or  to 
stain  them  either  black  or  brown  ;  these  are,  in  fact,  but 
modifications  of  one  process. 

To  obtain  the  golden  orange  color  characteristic  of 
brasses  rich  in  copper,  the  piece  may  be  polished  and  im- 
mersed in  a  warm  bath  of  the  neutral  solution  of  crystallized 
acetate  of  copper  for  a  moment,  washing  in  clean  water  and 
rubbing  dry  and  bright.  The  chloride  of  antimony  gives  a 
dark  rich  violet  color,  if  the  article  is  heated  to  nearly  the 
boiling  point  of  water ;  sulphate  of  copper  gives  a  watered 
surface  and  copper  nitrate  a  black. 

Larkin  used  the    hydrochlorate    of  copper  with  a  little 


238  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 


free  nitric  acid,  largely  diluted,  to  produce  a  dark  bronze; 
a  little  acetic  acid  added  to  the  solution  of  the  same  salt  gave 
a  copper  color,  and  the  patina  of  antique  bronze  was  imitated 
by  adding  ammonia  solution  in  large  amount,  or  a  quantity  of 
sal  ammoniac. 

"  Bronze"  paints  are  used  for  giving  to  the  surface  of  iron, 
or  of  any  other  material,  the  appearance  of  bronze ;  they 
have  a  great  variety  of  composition ;  some  are  composed  of 
filings,  or  powder,  of  brass  mixed  in  some  oil  paint  which 
does  not  conceal  the  color  of  the  bronze. 

Graham's  bronzing  liquids,  as  published  in  1861,*  have  a 
great  range  of  composition  and  of  application  as  follows : 

TABLE  XXXII. 

BRONZING   LIQUIDS. 

To  be  used  for  Brass  by  simple  Immersion. 


\ 

i 

"o 

"i 

& 
f 

e  of  arsenic. 

_o 

tion  of  sulphur. 

| 

3 

rs 

potassium. 

de  of  potassium  sol. 

lide  of  potassium. 

ite  of  soda. 

No. 

a 

»rt 

Nitrate  of  i 

Perchlorid< 

s 

Nitrate  of  < 

Tersulphid 

Muriate  of 

Potash  sok 

Pearlash  sc 

Cyanide  of 

Ferrocyani 

Sulphocyai 

Hyposulph 

Nitric  acid. 

Oxalic  acid 

i 

pt. 

dr. 

5 

dr. 

Pt. 

oz. 

gr. 

oz. 

dr. 

dr. 

oz. 

pt. 

dr. 

dr. 

dr. 

oz. 

j  Brown,  and  every 

2 

T 

5 

J     shade  to  black. 

16 

16 

(  Brown,  and  every 

16 

J     shade  to  red. 

5 

i 

Brownish  red. 

6 

\ 

3° 

6 

*  * 

Yellow  to  red 

g 

10 

i 

Olive-green. 

II 

5 

Slate 

12 

Blue 

13 

Steel-gray. 

r4 

2 

10 

Black. 

In  the  preparation  of  No.  5,  the  liquid  must  be  brought  to  boil  and  cooled.  In  using 
No.  13,  the  heat  of  the  liquid  must  not  be  under  180°  F.  No.  6  is  slow  in  action,  taking  an 
hour  to  produce  good  results.  The  action  of  the  others  is,  for  the  most  part,  immediate. 


*  Brass  Founders'  Manual,  Lond.  1870. 


MANUFACTURE  AND   WORKING  OF  ALLOYS. 

TABLE    XXXII.— Continued. 
To  be  used  for  Copper  by  simple  Immersion. 


239 


6 

c 

§ 

. 

i 

•d 

O- 

•- 

c 

0 

'n 

" 

(• 

ti 

p 

Q 

rt 

3 

2 

u 

No. 

i 

Nitrate  of  ii 

Sulphate  of 

Sulphide  of 

Sulphur. 

Muriate  of 

Pearlash. 

Sulphocyan 

Hyposulphi 

1 

I 

pt. 

dr. 

oz. 

dr. 

dr. 

dr. 

oz. 

dr. 

oz. 

dr. 

Brown,  and  every  shade  to  black. 

16 

5 

2 

Dark-brown  drab. 

17 

i 

i 

2 

18 

2 

j 

Bright  red. 

ig 

i 

i 

Red,  and  every  shade  to  black. 

20 

•• 

i 

•• 

•• 

•• 

Steel-gray,  at  180°  F. 

For  Zinc. 


i 

0 
V 

j 

8 

1 

ide  of  potassium. 

te  of  soda. 

1 

8 
1 

*o 

% 

0 

'3 

"o 

1 

•g. 

g 

No. 

1 

Nitrate 

1 

1 
1 

Muriate 

Muriate 

1 

1 

I 

>. 

- 

Garanci 

! 

pt. 

dr. 

dr. 

dr. 

dr. 

oz. 

oz. 

dr. 

dr. 

Black 

- 

i 

Dark  grav 

* 

a 

26 

Green-gray 

27 

X 

Red  boil. 

28 

r 

jj 

•• 

4 

•j 

•• 

Copper  color.    Plates  so  c  A  *. 
Copper  color  with  agitation 

X 

Purple  boil 

145.  Lacquering  is  the  process  of  covering  a  polished 
surface  of  brass  or  of  other  metal  with  a  transparent  or  trans- 
lucent coating,  which,  while  protecting  it  from  oxidation  and 


*  Made  to  the  consistency  of  cream. 


240  MATERIALS  OF  ENGINEERING-NON-FERROUS  METALS. 

discoloration,  does  not  wholly  conceal  it.  It  is  a  process  of 
varnishing  polished  metal.  It  is  applied  also  to  the  surfaces 
of  bronzed  objects.  Lacquer  is  a  solution,  usually,  of  some 
vegetable  gum  or  resin  in  alcohol  or  other  effective  colorless 
solvent.  In  its  application,  great  care  is  taken  to  keep  the 
piece  to  be  lacquered  warm  and  of  uniform  temperature,  to 
apply  the  solution  quickly,  smoothly  and  uniformly.  The 
usual  solution  is  "  shellac  "  in  alcohol,  and  the  best  can,  as  a 
rule,  be  made  with  the  "  stick "  lac.  It  may  be  colored  by 
any  permanent  transparent  alchoholic  solution  giving  the 
desired  tint.  The  red  coloring  matters  are,  usually,  dragon's 
blood,  red  saunders  or  annotto ;  the  yellow  are  gamboge, 
sandarac,  saffron,  turmeric  or  aloes.  The  following  is 
Graham's  table  of  lacquers  : 


TABLE    XXXIII. 

LACQUERS. 


SOLUTIONS. 

REDS. 

YELLOW. 

V 

a 

fj 

I 

Q 

J 

| 

u 

J3 
V 

1 

> 

%    -o 

jrt        O 

*rt 

? 

•J 

^ 

4) 

0     *x 

d 

No 

Shellac. 

d 

s 

Canada  B 

Spirits  of 

Pyro-acet 

Spirits  of 

Turpentir 

a    ,« 

<H      § 

C-       bjO 

c/5  '  Q 

Annotto. 

Saunders. 

Turmeric 

Gamboge 

Saffron. 

0 

< 

a 
U 

Sandarac. 

oz. 

dr. 

dr. 

Pt. 

oz. 

clr. 

oz. 

Pt. 

dr. 

dr. 

gr- 

dr. 

dr. 

dr. 

dr. 

dr. 

i 

2 

4 

i 

Strong  simple. 

3        T  ' 

5         i 

i 

i 

16 

4 

8 

« 

6 

2 

. 

i 

8 

.. 

32 

8 

Plate  gold. 

7 

Pale  yellow 

8 

5 

"           Ross's 

Q 

! 

4 

Full  yellow. 

10 

3 

2 

16 

Gold 

ii 

3 

6 

64 

6 

T4 

12 

i 

20 

2 

5 

li 

13 

3 

Tfi 

Deep  gold 

4 

3 

3 

30 

40 

12 

10 

« 

6       .. 
7        i 

•• 

i 

8 

8 

32 

Red. 

?      15 

3° 

30      6 

20 

60 

IO 

Tin  lacquer. 

19  i    " 

i 

4 

i 

Green,  for  bronze 

The  union  of  red  with  yellow  produces  a  fine  orange  color. 


MANUFACTURE  AND   WORKING  OF  ALLOYS. 


241 


The  lacquers  are  kept  in  carefully  stoppered  bottles,  and 
it  is  better  that  they  should  be  of  opaque  material,  or  of 
glass  impenetrable  by  actinic  light  capable  of  altering  them  ; 
yellow  glass  is  sometimes  used.  When  in  use,  they  are 
poured  into  dishes  of  convenient  size  and  form  and  are  laid 
on  with  a  thin,  wide  flat  brush.* 

"  Clouding "  is  performed  by  pouring  on  the  surface  a 
mixture  of  fine  charcoal  dust  in  water,  stirring  it  to  obtain  the 
pattern,  and  then  drying.  The  work  is  finally  lacquered. 


TABLE  OF  SOLDERS.    (See  p.  221.) 

{Mechanical  World.} 


No.                           Name. 

Compositions. 

Flux. 

Fluxing 
Point. 

i    Plumbers'  coarse  solder  .       .         ... 

Tin,  i     lead,  3  

R 

800°  Fahr. 

Tin,  i     lead,  2 

R 

441° 

Tin   i     lead  2 

R 

3  70 

4    Tinners'  solder                                  .... 

Tin,  i\  •  lead,  i  

RorZ 

004° 

5    Tinners'  fine  solder  

Tin,  2     lead,  i  

RorZ 

340° 

6    Hard  solder  for  copper,  brass,  iron.. 
7    Hard  solder  lor  copper,  brass,  iron.. 
8    Hard  solder  for  copper,  brass,  iron 
more  fusible  than  6  or  7 

Copper,  2  ;  zinc,  i  
Good,  tough  brass,  5  ;  zinc,  i. 

Copper,  i  •  zinc,  i  .  .  . 

B 
B 

B 

9    Hard  solder  for  copper,  brass,  iron.  . 
10    Silver  solder  for  jewellers  

Good  tough  plate  brass  
Silver,  19  ;  copper,  i  ;  brass,  i 

B 
B 

ii    Silver  solder  for  plating  
12    Silver  solder  for  silver,  brass,  iron  .  . 
13    Silver  solder  for  steel  joints  

Silver,  2  ;  brass,  i  
Sil  ver,  i  ;  brass,  i  
Silver,  19  ;  copper,  i  ;  brass,  i 

B 
B 
B 

14    Silver  solder  more  fusible  ...           ... 

Silver,  5  ;  brass,  5  ;  zinc,  5  ... 

B 

15    Gold  solder                                  

Gold    12  •  silver,  2  •  copper,  4 

B 

16    Bismuth  solder  
17    Bismuth  solder      .                   

Lead,  4  ;  tin,  4  ;  bismuth,  i.. 
Lead,  3  •  tin,  3  ;  bismuth,  i  .  . 

RorZ 
RorZ 

320° 

310° 

18    Bismuth  solder  

Lead,  2  ;  tin,  2  ;  bismuth,   i.  . 

RorZ 

!92° 

19    Bismuth  solder            

Lead,  2  ;  tin,  i  ;  bismuth,  2.  . 

RorZ 

236° 

20    Bismuth  solder 

Lead   3  •  tin,  5  ;  bismuth,  3  . 

RorZ 

2^2° 

21    Pewterers'  solder  .  .  . 

Lead  4  •  tin   3  •  bismuth,  2 

RorZ 

Abbreviations  :  R,  resin  ;  B,  borax  ;  Z,  chloride  of  zinc. 


*  Vide  Part  I,  §  196,  p.  335,  for  lacquers  and  browning  liquids  for  fire-arms, 


etc. 


16 


CHAPTER  VIII. 

STRENGTH,   ELASTICITY   AND   DUCTILITY    OF  THE   NON- 
FERROUS   METALS. 

146.  The  Strength  of  Non-ferrous  Metals  and   other 
mechanical   properties  have  not  attracted  as  much   attention 
as  the    engineer   would    desire.      Investigations    have   been 
few   in  number,    generally    very    incomplete,    and   as  a  rule 
unfruitful,  in    comparison    with    those   relating  to   iron   and 
steel. 

In  recording  and  discussing  experimental  work  on  the 
non-ferrous  metals  and  their  alloys,  the  system  and  nomen- 
clature adopted  will  be  that  employed  in  the  study  of  the 
strength  of  iron  and  steel.  The  following  summary  will  here 
suffice. *  Following  it,  will  be  given  a  statement  of  the  re- 
sults of  experiments  made  upon  the  non-ferrous  metals,  suc- 
ceeded by  chapters  describing  investigations  of  the  strength 
and  elasticity  of  their  alloys,  and  the  conditions  modifying 
strength. 

147.  The  Resistance  of  Metal  to  rupture  may  be  brought 
into  play  by  either  of  several  methods  of  stress,  which  have 
been  thus  divided  by  the  Author: 

Longitudinal j  Tensile  :  resisting  pulling  force. 

(  Compression  :  resisting  crushing  force. 

(  Shearing  :  resisting  cutting  across. 

Transverse J  Bencijng  .   resisting  cross  breaking. 

(  Torsional :   resisting  twisting  stress. 

*  Abridged  and  adapted  from  Part  II.,  Chapter  IX.  For  the  theory  of  the 
elasticity  and  strength  of  materials,  consult  "Wood's  Resistance  of  Materials," 
published  by  J.  Wiley  &  Sons,  and  Burr's  work  on  the  same  subject  issued  by 
the  same  publishers. 


STRENGTH  OF  NON-FERROUS  METALS.  243 

When  a  load  is  applied  to  any  part  of  a  structure  or  of  a 
machine  it  causes  a  change  of  form,  which  may  be  very 
slight,  but  which  always  takes  place,  however  small  the  load. 
This  change  of  form  is  resisted  by  the  internal  molecular 
forces  of  the  piece,  i.e.,  by  its  cohesion.  The  change  of  form 
thus  produced  is  called  strain,  and  the  acting  force  is  a  stress. 

The  Ultimate  Strength  of  a  piece  is  the  maximum  resist- 
ance under  load — the  greatest  stress  that  can  exist  before 
rupture.  The  Proof  Strength  is  the  load  applied  to  deter- 
mine the  value  of  the  material  tested  when  it  is  not  intended 
that  observable  deformation  shall  take  place.  It  is  usually 
equal,  or  nearly  so,  to  the  maximum  elastic  resistance  of  the 
piece.  It  is  sometimes  said  that  this  load,  long  continued, 
will  produce  fracture ;  but,  as  will  be  seen  hereafter,  this  is 
not  necessarily,  even  if  ever,  true. 

The  Working  Load  is  that  which  the  piece  is  proportioned 
to  bear.  It  is  the  load  carried  in  ordinary  working,  and  is 
usually  less  than  the  proof  load,  and  is  always  some  fraction, 
determined  by  circumstances,  of  the  ultimate  strength. 

A  Dead  Load  is  applied  without  shock,  and,  once  applied, 
remains  unchanged,  as,  e.g.,  the  weight  of  a  bridge;  it  pro- 
duces a  uniform  stress.  A  Live  Load  is  applied  suddenly, 
and  may  produce  a  variable  stress,  as,  e.g.,  by  the  passage  of 
a  railroad  train  over  a  bridge. 

The  Distortion  of  the  strained  piece  is  related  to  the  load 
in  a  manner  best  indicated  by  strain  diagrams.  Its  value  as 
a  factor  of  the  measure  of  shock-resisting  power,  or  of  re- 
silience, is  exhibited  in  a  later  article.  It  also  has  importance 
as  indicating  the  ductile  qualities  of  the  metal. 

The  Reduction  of  Area  of  Section  under  a  breaking  load  is 
similarly  indicative  of  the  ductility  of  the  material,  and  is  to 
be  noted  in  conjunction  with  the  distortion. 

E.g.  A  considerable  reduction  of  section  with  a  smaller 
proportional  extension  would  indicate  a  lack  of  homogeneous- 
ness,  and  that  the  piece  had  broken  at  the  soft  part  of  the 
bar.  The  greater  the  extension  in  proportion  to  the  reduc- 
tion of  area  in  tension,  the  more  uniform  the  character  of  the 
metal. 


244  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


148.  Factors  of  Safety. — The  ultimate  strength,  or  maxi- 
mum capacity  for  resisting  stress,  has  a  ratio  to  the  maximum 
stress  due  to  the  working  load,  which,  although  less  in  metal 
than  in  wooden  or  stone  structures,  is,  nevertheless,  made  of 
considerable  magnitude  in  many  cases.  It  is  much  greater 
under  moving  than  under  steady  "  dead  "  loads,  and  varies 
with  the  character  of  the  material  used.  For  machinery  it  is 
usually  6  or  8  ;  for  structures  erected  by  the  civil  engineer, 
from  5  to  6.  The  following  may  be  taken  as  minimum  values 
of  this  "  factor  of  safety  for  the  non-ferrous  metals:  " 


LOAD. 

MATERIAL 

SHOCK 

Dead. 

Live. 

Copper  and  other  soft  metals 

Ratio  of  Ultimate 

and  alloys  

5 

8 

10  + 

Strength  to 

The  brittle  metals  and  alloys  . 

4 

7 

10  to  15 

Working  Load. 

The  Proof  Strength  usually  exceeds  the  working  load  from 
50  per  cent.,  with  tough  metals,  to  200  or  300  per  cent,  where 
brittle  materials  are  used.  It  should  usually  be  below  the 
elastic  limit  of  the  material. 

As  this  limit,  with  brittle  materials,  is  often  nearly  equal 
to  their  ultimate  strength,  a  set  of  factors  of  safety,  based  on 
the  elastic  limit,  would  differ  much  from  those  above  given 
for  ductile  metals,  but  would  be  about  the  same  for  all  brittle 
materials,  thus : 


MATERIAL. 

LOAD. 

SHOCK. 

Dead. 

Live. 

Soft  metals.  ... 

2 

3 

4 
6 

6 

8  to  12 

Ratio  of  Elastic 
Resistance  to 
Working  Load. 

Brittle  metals  and   alloys.  .  .  . 

The  figure  given  for  shock  is  to  be  taken  as  approximate, 
but  used  only  when  it  is  not  practicable  to  calculate  the 
energy  of  impact  and  the  resilience  of  the  piece  meeting  it, 
and  thus  to  make  an  exact  calculation  of  proportions. 


STRENGTH  OF  NON-FERROUS 


The  factors  of  safety  adopted  for  non-ferrous  metals  are 
higher  than  those  usually  adopted  for  construction  in  iron  or 
steel  in  consequence  of  the  fact  that  the  elastic  limit  and  the 
elastic  resilience,  or  shock-resisting  power,  of  the  latter  seem 
to  increase  with  strain,  up  to  a  limit;  while  the  former 
gradually  yield  under  comparatively  low  stresses,  as  will  be 
seen  hereafter.  In  common  practice,  the  factor  of  safety 
covers  not  only  risks  of  injury  by  accidental  excessive 
stresses,  but  deterioration  with  time,  uncertainty  as  to  the 
character  of  uninspected  material,  and  sometimes  equally 
great  uncertainty  as  to  the  absolute  correctness  of  the  for- 
mulas and  the  constants  used  in  the  calculations.  As  inspec- 
tion becomes  more  efficient  and  trustworthy;  as  our  knowl- 
edge of  the  effect  of  prolonged  and  of  intermittent  stress 
becomes  more  certain  and  complete;  as  our  formulas  are 
improved  and  rationalized,  and  as  their  empirically  deter- 
mined constants  are  more  exactly  obtained,  the  factor  of 
safety  is  gradually  reduced,  and  will  finally  become  a  mini- 
mum when  the  engineer  acquires  the  ability  to  assume  with 
confidence  the  conditions  to  be  estimated  upon,  and  to  say 
with  precision  how  his  materials  will  continuously  carry  their 
loads. 

A  characteristic  distinction  between  the  ductile  non-ferrous 
metals  and  ductile  iron  or  steel,  is  that  the  former  have 
usually,  as  purchased,  no  true  elastic  limit,  but  yield  to  small 
stresses  without  recovery  of  form  and  their  permanent  set 
equals  their  maximum  distortion.  Where  brittle,  they  are 
often  very  elastic,  however,  and  recover  fully.  In  such  cases, 
the  elastic  limit  coincides  with  their  ultimate  resistance  to 
fracture,  as  is  the  case  with  glass,  hard  cast  iron,  and  often 
with  hardened  steel. 

In  the  table  above  it  is  assumed  that  an  elastic  limit 
occurs  at  the  point  at  which  the  elongation  becomes  o.ooio  of 
the  total  length  of  the  piece  stretched. 

In  some  cases  it  is  advisable  to  design  some  minor  part, 
or  element,  of  a  train  with  a  lower  factor  of  safety,  to  insure 
that  when  a  breakdown  does  occur  it  shall  be  certain  to  take 
place  where  it  will  do  least  harm. 


246  MATERIALS  OF  ENGINEERING—  NON-FERROUS  METALS. 

149.  The  Measure  of  Resistance  to  strain  is  determined, 
in  form,  by  the  character  of  the  stress.  By  stress  is  here 
understood  the  force  exerted,  and  by  strain  the  change  of 
form  produced  by  it. 

Tenacity  is  resistance  to  a  pulling  stress,  and  is  measured 
by  the  resistance  of  a  section,  one  unit  in  area,  as  in  pounds 
or  tons  on  the  square  inch,  or  in  kilogrammes  per  square  cen- 
timetre or  square  millimetre.  Then,  if  T  represents  the 
tenacity  and  K  is  the  section  resisting  rupture,  the  total  load 
that  can  be  sustained  is,  as  a  maximum, 

P=TK    ........     (i) 

Compression  is  similarly  measured,  and  if  C  be  the  maxi- 
mum resistance  to  crushing  per  unit  of  area,  and  AT  the  sec- 
tion, the  maximum  load  will  be 

P=CK    ........     (2) 

Shearing  is  resisted  by  forces  expressed  in  the  same  way, 
and  the  maximum  shearing  stress  borne  by  any  section  is 


(3) 


Bending  Stresses  are  measured  by  moments  expressed  by 
the  product  of  the  bending  effort  into  its  lever-arm  about  the 
section  strained,  and  if  P  is  the  resultant  load,  /  the  lever-arm 
and  J/the  moment  of  resistance  of  the  section  considered, 


Pl=M 


Torsional  Stresses  are  also  measured  by  the  moment  of 
the  stress  exerted,  and  the  quantity  of  attacking  and  resist- 
ing moments  is  expressed  as  in  the  last  case. 

Elasticity  is  measured  by  the  longitudinal  force,  which, 
acting  on  a  unit  of  area  of  the  resisting  section,  if  elasticity 
were  to  remain  unimpaired,  would  extend  the  piece  to  double 
its  original  length.  Within  the  limit  at  which  elasticity  is 
unimpaired,  the  variation  of  length  is  proportional  to  the 


STRENGTH  OF  NON-FERROUS  METALS.  247 

force  acting,  and  if  E  is  the  "Modulus  of  Elasticity"  or 
"Young's  Modulus,"  /  the  length,  and  e  the  extension,  P 
being  the  total  load,  and  K  the  section  : 


eK 
PI 


The  Coefficients  entering  into  these  several  expressions  for 
resistance  of  materials  are  often  called  Moduli,  and  the  forms 
of  the  expressions  in  which  they  appear  are  deduced  by  the 
Theory  of  the  Resistance  of  Materials,  and  the  processes  are 
given  in  detail  in  works  on  that  subject. 

These  moduli,  or  coefficients,  as  will  be  seen,  have  values 
which  are  rarely  the  same  in  any  two  cases  ;  but  vary  not 
only  with  the  kind  of  material,  but  with  every  variation,  in 
the  same  substance,  of  structure,  size,  form,  age,  chemical 
composition  or  physical  character,  with  every  change  of  tem- 
perature, and  even  with  the  rate  of  distortion  and  method  of 
action  of  the  distorting  force.  Values  for  each  familiar  ma- 
terial, for  a  wide  range  of  conditions,  will  be  given  in  the 
following  pages. 

150.  Method  of  Resistance  to  Stress.  —  When  a  piece  of 
metal  is  subjected  to  stress  exceeding  its  power  of  resistance 
for  the  moment,  and  gradually  increasing  up  to  the  limit  at 
which  rupture  takes  place,  it  yields  and  becomes  distorted  at 
a  rate  which  has  a  definitely  variable  relation  to  the  magni- 
tude of  the  distorting  force  ;  this  relation,  although  very 
similar  for  all  metals  of  any  one  kind,  differs  greatly  for  differ- 
ent metals,  and  is  subject  to  observable  alteration  by  every 
measurable  difference  in  chemical  composition  or  in  physical 
structure. 

Thus,  in  Fig.  2,  let  this  operation  be  represented  by  the 
several  curves,  a,  b,  c,  d,  etc.,  the  elevation  of  any  point  on 
the  curve  above  the  axis  of  abscissas,  OX,  being  made  pro- 
portional to  the  resistance  to  distortion  of  the  piece,  and  to 
the  equivalent  distorting  stress,  at  the  instant  when  its  dis- 


248  MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS. 

tance  from  the  left  side  of  the  diagram,  or  the  axis  of  ordi- 
nates,  OY,  measures  the  coincident  distortion.  As  drawn,  the 
strain-diagram,  a  a  ,  is  such  as  would  be  made  by  a  soft  metal 
like  tin  or  lead  ;  b  b'  represents  a  harder,  and  c  c'  a  still  harder 
and  stronger  metal,  as  zinc  and  rolled  copper.  If  the  smallest 
divisions  measure  the  per  cent,  of  extension  horizontally,  and 
10,000  pounds  per  square  inch  (703  kilogrammes  per  square 
centimetre)  vertically,  d d ',  would  fairly  represent  a  hard  iron, 
or  a  puddled  or  a  "  mild  "  steel ;  while//'  and  gg'  would  be 
strain  diagrams  of  hard,  and  of  very  hard  tool  steels,  respect- 
ively. 

The  points  marked  e,  e't  e",  etc.,  are  the  so-called  **  elastic 


FIG.  2. — STRAIN-DIAGRAMS. 

limits'"  at  which  the  rate  of  distortion  more  or  less  suddenly 
changes,  and  the  elevation  becomes  more  nearly  equal  to  the 
permanent  change  of  form,  and  at  these  points  the  resistance 
to  further  change  increases  much  more  slowly  than  before. 
This  change  of  rate  of  increase  in  resistance  continues  until 
a  maximum  is  reached,  and,  passing  that  point,  the  piece 
either  breaks,  as  at/'  and^',  or  yields  more  and  more  easily 
until  distortion  ceases,  or  until  fracture  takes  place,  and  it 
becomes  zero  at  the  base  line,  as  at  X. 

Such  curves  have  been  called  by  the  Author  "  Strain- 
diagrams." 

151.  Equations  of  Curves  of  Resistance  or  Strain-dia- 
grams.— These  curves  are,  at  the  start,  often  nearly  para- 


STRENGTH  OF  NON-FERROUS  METALS.  249 

bolic,  and  the  strain-diagrams  of  cast  iron,  /*,  i,  k,  having  their 
origin  at  <?,  are  usually  capable  of  being  quite  accurately  ex- 
pressed by  an  equation  of  the  parabolic  form,  as 


in  which  the  Author  found  the  constants  for  copper  in  tension 
to  be 

A  =  10,000,000 ;   B  —  100,000,000, 

£ 

and  where  —  is  the  ratio  of  elongation  to  the  length  of  the 

piece,  and  P,  the  load,  is  measured  for  tension,  in  pounds  on 
the  square  inch  of  resisting  section. 

For  bronze  of  fair  quality,  the  Author  has,  in  some  ex- 
periments, obtained : 

A  =  12,000,000;   B  —  50,000,000. 
For  brass,  he  obtained  nearly  : 

A  =  12,000,000 ;  B  —  50,000,000. 

The  coefficient  A,  above,  is  the  modulus  of  elasticity. 
Reducing  the  above  quantities  to  metric  measure — kilo- 
grammes on  the  square  centimetre — we  have : 

A.  B. 

For  copper 703,000  7,030,000 

For  bronze 843,600  3,515,000 

For  brass 843,600  3,515,000 

152.  The  Series  of  Elastic  Limits. — If,  at  any  moment, 
the  stress  producing  distortion  is  relaxed,  the  piece  recoils 
and  continues  this  reversed  distortion  until,  all  load  being 
taken  off,  the  recoil  ceases  and  the  piece  takes  its  "  per- 
manent set."  This  change  is  shown  in  the  figure  at/"/", 
the  gradual  reduction  of  load  and  coincident  partial  restora- 
tion of  shape  being  represented  by  a  succession  of  points 
forming  the  line  /"/",  each  of  which  points  has  a  position 
which  is  determined  by  the  elastic  resistance  of  the  piece  as 


250  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

now  altered  by  the  strain  to  which  it  has  been  subjected. 
The  distance  Of"  measures  the  permanent  set,  and  the  dis- 
tance/"/'" measures  the  recoil. 

The  piece  now  has  qualities  which  are  quite  different  from 
those  which  distinguished  it  originally,  and  it  may  be  re- 
garded as  a  new  specimen  and  as  quite  a  different  metal.  Its 
strain-diagram  now  has  its  origin  at/",  and  the  piece  being 
once  more  strained,  its  behavior  will  be  represented  by  the 
curve/"/"  evl  /',  a  curve  which  often  bears  little  resemblance 
to  the  original  diagram  (9,  /,  /'.  The  new  diagram  shows  an 
elastic  limit  at  ev,  and  very  much  higher  than  the  original 
limit  elv.  Had  this  experiment  been  performed  at  any  other 
point  along  the  line//',  the  same  result  would  have  followed. 
It  thus  becomes  evident  that  the  strain-diagram  is  a  curve  of 
elastic  limits,  each  point  being  at  once  representative  of  the 
resistance  of  the  piece  in  a  certain  condition  of  distortion, 
and  of  its  elastic  limit  as  then  strained. 

The  ductile,  non-ferrous  metals,  and  iron  and  steel,  and 
the  truly  elastic  substances,  have  this  in  common — that  the 
effect  of  strain  is  to  produce  a  change  in  the  mode  of  resist- 
ance to  stress,  which  results,  in  the  latter,  in  the  production 
of  a  new  and  elevated  elastic  limit,  and  in  the  former  in  the 
introduction  of  such  a  limit  where  none  was  observable  be- 
fore. 

It  becomes  necessary  to  distinguish  these  elastic  limits  in 
describing  the  behavior  of  strained  metals,  and,  as  will  be 
seen  subsequently,  the  elastic  limits  here  described  are,  under 
some  conditions,  altered  by  strain,  and  we  thus  have  another 
form  of  elastic  limit  to  be  defined  by  a  special  term. 

In  this  work  the  original  elastic  limit  of  the  piece  in  its 
ordinary  state,  as  at  e,  e't  e",  etc.,  will  be  called  either  the 
Original,  or  the  Primitive,  Elastic  Limit,  and  the  elastic  limit 
corresponding  to  any  point  in  the  strain-diagram  produced 
by  gradual,  unintermitted  strain,  will  be  called  the  Normal 
Elastic  Limit  for  the  given  strain.  It  is  seen  that  the  dia- 
gram representing  this  kind  of  strain  is  a  Curve  of  Normal 
Elastic  Limits. 

The  elastic  limit  is  often  said  to  be  that  point  at  which 


STRENGTH  OF  NON-FERROUS  METALS.  251 

a  permanent  set  takes  place.  As  will  be  seen  on  studying 
actual  strain-diagrams  to  be  hereafter  given,  and  which 
exhibit  accurately  the  behavior  of  the  metal  under  stress, 
there  is  no  such  point.  The  elastic  limit  referred  to  ordina- 
rily, when  the  term  is  used,  is  that  point  within  which  recoil, 
on  removal  of  load,  is  approximately  equal  to  the  elongation 
attained  and  beyond  which  set  becomes  nearly  equal  to  total 
elongation. 

It  is  seen  that,  within  the  elastic  limit,  sets  and  elongations 
are  similarly  proportional  to  the  loads,  that  the  same  is  true 
on  any  elastic  line,  and  that  loads  and  elongations  are  nearly 
proportional  everywhere  beyond  the  elastic  limit,  within  a 
moderate  range,  although  the  total  distortion  then  bears  a 
far  higher  ratio  to  the  load,  while  the  sets  become  nearly 
equal  to  the  total  elongations. 

153.  Effect  of  Shock  or  Impact ;  Resilience.— The  be- 
havior of  metals,  under  moving,  or  "  live,"  load  and  under 
shock,  is  not  the  same  as  when  gradually  and  steadily  strained 
by  a  slowly  applied  or  static  stress.  In  the  latter  case,  the 
metal  undergoes  the  changes  illustrated  by  the  strain 
diagrams,  until  a  point  is  reached  at  which  equilibrium  occurs 
between  the  applied  load  and  resisting  forces,  and  the  body 
rests  indefinitely,  as  under  a  permanent  load,  without  other 
change  occurring  than  such  settlement  of  parts  as  will  bring 
the  whole  structural  resistance  into  play. 

When  a  freely  moving  body  strikes  upon  the  resisting 
piece,  on  the  other  hand,  it  only  comes  to  rest  when  all  its 
kinetic  energy  is  taken  up  by  the  resisting  piece ;  there  is 
then  an  equality  of  vis  viva  expended  and  work  done,  which 
is  expressed  thus : 

WV*      (s 

=     p  dx  —pms\ 

%g        I* 

in  which  expression  W  is  the  weight  of  the  striking  body,  V 
its  velocity,  /  the  resisting  force  at  any  instant,  pm  the  mean 
resistance  up  to  the  point  at  which  equilibrium  occurs,  and  s 
is  the  distance  through  which  resistance  is  met. 


252   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

As  has  been  seen,  the  resistance  may  usually  be  taken  as 
varying  approximately  with  the  ordinates  of  a  parabola,  the 
abscissas  representing  extensions.  The  mean  resistance  is, 
therefore,  nearly  two-thirds  the  maximum,  and 


WV2      fj 

r  =  \pdx=pms  =  y^et^ae*,  nearly       .     .     (8) 

2«£~  J  o 


where  e  is  the  extension,  and  /  the  maximum  resistance  at 
that  extension,  and  a  a  constant.  Brittle  materials,  like  hard 
bronzes  and  brasses,  have  a  straight  line  for  their  strain- 
diagrams,  and  the  coefficient  becomes  ^  instead  of  %,  and 


WV2  £* 

*  ...     (9) 


2g  *    E 

154.  Resilience,  or  Spring,  is  the  work  of  resistance  up 
to  the  elastic  limit.  This  will  be  called  Elastic  Resilience. 
The  modulus  of  elasticity  being  known,  the  Modulus  of 
Elastic  Resilience  is  obtained  by  dividing  half  the  square  of 
the  maximum  elastic  resistance  by  the  modulus  of  elasticity, 
E,  as  above,  and  the  work  done  to  the  "primitive  elastic 
limit "  is  obtained  by  multiplying  this  modulus  of  resilience 
by  the  volume  of  the  bar.* 

The  total  area  of  the  diagram,  measuring  the  total  work 
done  up  to  rupture,  will  be  called  a  measure  of  Total  we  Ulti- 
mate Resilience.  Mallett's  Coefficient  of  Total  Resilience  is 
the  half  product  of  maximum  resistance  into  total  extension. 
It  is  correct  for  brittle  substances  and  all  cases  in  which  the 
primitive  elastic  limit  is  found  at  the  point  of  rupture.  With 
tough  materials,  the  coefficient  is  more  nearly  two-thirds — 
and  'may  be  even  greater  where  the  metal  is  very  ductile,  as, 
e.g.,  pure  copper,  tin,  or  lead.  Unity  of  length  and  of  section 

*  Rankine  and  some  other  writers  take  this  modulus  as  — ,  instead  of  £  —  > 


STRENGTH   OF  NON-FERROUS  METALS.  2$$ 

being  taken,  this  coefficient  is  here  called  the  Modulus  of 
Resilience. 

When  the  energy  of  a  striking  body  exceeds  the  total  re- 
silience of  the  material,  the  piece  will  be  broken.  When  the 
energy  expended  is  less,  the  piece  will  be  strained  until  the 
work  done  in  resistance  equals  that  energy,  when  the  striking 
body  will  be  brought  to  rest. 

As  the  resistance  is  partly  due  to  the  inertia  of  the 
particles  of  the  piece  attacked,  the  strain-diagram  area  is 
always  less  than  the  real  work  of  resistance,  and,  at  high  ve- 
locities, may  be  very  considerably  less,  the  difference  being 
expended  in  the  local  deformation  of  that  part  of  the  piece 
at  which  the  blow  is  received.  In  predicting  the  effect  of  a 
shock  it  is,  therefore,  necessary  to  know  not  only  the  energy 
stored  in  the  moving  mass  and  the  method  of  variation  of  the 
resistance,  but  also  the  striking  velocity.  To  meet  a  shock 
successfully  it  is  seen  that  resilience  must  be  secured  sufficient 
to  take  up  the  shock  without  rupture,  or,  if  possible,  without 
serious  deformation.  It  is,  in  most  cases,  necessary  to  make 
the  elastic  resilience  greater  than  the  maximum  energy  of  any 
attacking  body. 

Moving  Loads  produce  an  effect  intermediate  between  that 
due  to  static  stress  and  that  due  to  the  shock  of  a  freely  mov- 
ing body  acting  by  its  inertia  wholly ;  these  cases  are,  there- 
fore, met  in  design  by  the  use  of  a  high  factor  of  safety,  as 
above. 

As  is  seen  by  a  glance  at  the  strain-diagram,  ff  (Fig.  2), 
the  piece  once  strained  has  a  higher  elastic  resilience  than  at 
first,  and  it  is  therefore  safer  against  permanent  distortion  by 
moderate  shocks,  while  the  approach  of  permanent  extension 
to  a  limit  renders  it  less  secure  against  shocks  of  such  great 
intensity  as  to  endanger  the  piece. 

When  the  shock  is  completely  taken  up,  the  piece  recoils, 
as  at  e*f"f"9  until  it  settles  at  such  a  point  on  that  line — as- 
suming the  shock  to  have  extended  the  piece  to  the  point  e* 
— that  the  static  resistance  just  equilibrates  the  static  load. 
This  point  is  usually  reached  after  a  series  of  vibrations  on 
either  side  of  it  has  occurred.  With  perfect  elasticity,  this 


254  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

point  is  at  one-half  the  maximum  resistance,  or  elongation, 
attained.     Thus  we  have 

WV* 
=  —.    .....    (.o) 


but/  varies  as  x  within  the  elastic  limit,  which  limit  has  now 
risen  to  some  new  point  along  the  line  of  normal  elastic 
limits,  as  evi.  Taking  the  origin  at  the  foot  of/'/",  since 
the  variations  of  length  along  the  line  Ox  are  equal  to  the 
elongations  and  to  the  distances  traversed  as  the  load  falls, 
and  as  stresses  are  now  proportional  to  elongations, 

p=ax\    Wh=Ws;mdW=P    .     .     .     (u) 

when  the  resisting  force  is/,  the  elongations  x,  while  h  and  s 
are  maximum  fall  and  elongation,  and  P  is  the  maximum 
resistance  to  the  load  at  rest.  Then 


f*  f* 

/  dx=a    x  dx 

J  a  J  0 


-s2=Ws.:s=—  (12) 

2  a 


For  a  static  load,  if  s'  is  the  elongation, 

W 

lV=P=as'  /.  y-  —  . 
a 


Hence, 


and  the  extension  and  the  corresponding  stress  due  to  the 
sudden  application  of  a  load  are  double  those  produced  by  a 
static  load. 

Where  the  applied  load  is  a  pressure  and  not  a  weight, 
z.e.j  where  considerable  energy  in  a  moving  body  is  not  to  be 
absorbed,  as  in  the  action  of  steam  in  a  steam  engine,  the 
only  increase  of  strain  produced  by  a  suddenly  applied  load 
is  that  produced  by  the  inertia  of  such  of  those  parts  of  the 
mass  attacked  as  may  have  taken  up  motion  and  energy. 


STRENGTH  OF  NON-FERROUS  METALS.  255 

155.  Proportioning  to  Resist  Shock. — The  problem  of 
proportioning  parts  to  resist  shock  is  thus  seen  to  involve  a 
determination  of  the  energy,  or  "  living  force,"  of  the  load  at 
impact,  and  an  adjustment  of  proportion  of  section  and  shape 
of  piece  attacked  such  that  its  work  of  elastic  or  of  ultimate 
resilience,  whichever  is  taken  as  the  limit,  shall  exceed  that 
energy  in   a  proportion   measured   by  the   factor   of   safety 
adopted.     For  ordinary  live  loads  and  moderate  impact,  re- 
quiring no   specially   detailed    consideration,   the    factors  of 
safety   already   given    (Art.    148),    as   based    upon    ultimate 
strength   simply,   are   considered   sufficient ;    in   all   cases  of 
doubt,  or  when  heavy  shock   is  anticipated,  calculations  of 
energy  and  resilience  are  necessary,  and  these  demand  a  com- 
plete knoVvledge   of  the   character,   chemical,   physical,   and 
structural,    of   every   piece    involved,    of    its    resilience   and 
method  of  yielding  under  stress,  and  of  every  condition  in- 
fluencing the   application   of  the   attacking   force — in   other 
words,  a  complete   knowledge   of  the   material   used,  of  the 
members  constructed  of  it,  and  of  the  circumstances  likely  to 
bring  about  its  failure. 

The  form  of  such  parts  should  usually  be  determined  on 
the  assumption  that  deformation  may  some  time  occur,  and 
such  expedients  as  that  of  Hodgkinson  in  enlarging  the  sec- 
tion on  the  weaker  side,  as  well  as  the  adoption  of  a  larger 
factor  of  safety  based  on  ultimate  strength,  are  advisable. 

156.  The  Methods  of  Testing  and  the  construction  of 
the  machines  used  are  fully  described  in  Part  II.  of  this  work. 
The  form  of  test-piece  advisable,  and  standard  formulas,  and 
many  facts  relating  to  this  part  of  the  subject  may  be  there 
studied,  or  in  works  on  the  strength  of  materials. 

157.  Compression. — Resistance  to  Compression  is  measured 
by  the  same  process  as  in  testing  by  tension.     This  form  of 
resistance  is,  however,  governed  in  many  cases  by  different 
laws,  and  is  often  modified  by  the  size  and  shape  of  the  piece 
tested  to  even  greater  extent  than  is  resistance  to  tensile 
stress.     The  method  of  rupture  is  not  only  different  for  differ- 
ent materials,  but  it  is  different  with  pieces  of  the  same  metal 
for  every  difference  in  size,  shape,  or  proportion.     Thus,  a 


2$6  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

piece  of  copper  or  lead  is  soft  and  tough,  and,  in  the  form  of 
a  short  cylindrical  column,  will  gradually  yield  by  crushing 
until  it  assumes  the  form  of  a  cheese,  or  a  button;  the  same 
metal  in  longer  cylinders  will  yield  similarly,  until,  reaching  a 
certain  limit,  as  in  long  columns,  it  will  yield  by  bending 
laterally,  and  under  a  comparatively  small  load.  A  piece  ot 
speculum  metal,  or  of  other  brittle  metal  or  alloy,  will  break 
by  crushing  into  fragments,  and  will  break  up  the  more  com- 
pletely as  it  is  harder  and  more  brittle.  Extremely  hard 
metals  and  alloys  exhibit  no  sign  of  yielding  until  their  limit 
of  resistance  is  reached,  when  they  suddenly  fly  to  pieces  with 
great  violence. 

In  all  cases,  resistance  increases  up  to  a  limit  beyond 
which  the  piece  usually  gives  way  suddenly,  if  the  metal  be 
hard  or  brittle  ;  while  ductile  and  malleable  metals  often  offer 
constantly  increasing  resistance,  the  limit  being  reached  only 
when  the  pressure  becomes  so  great  as  to  cause  the  metal  to 
flow  steadily,  as  is  illustrated  in  the  manufacture  of  lead 

Pipe- 
In  consequence  of  these  variations  due  to  form  and  size, 
it  is  even   more   necessary  than  when   testing  by  tension  to 
have  a  standard  form  of  test-piece,  as  proposed  in  Part  II., 
and  to  report  all  observations  as  made  upon  such  standard. 

158.  The  Structure  of  the  Piece  and  its  Chemical  Com- 
position determine  the  compressive  resistance  of  metals  and 
alloys.     With  pure,  well-worked  metal,  the  resistance  follows 
pretty  closely  a  law  peculiar  to   and  characteristic  of  each 
metal.     Within  the  elastic  limit,  the   behavior  of  the  piece 
may  be  taken  as  the  same,  whether  under  tension  or  compres- 
sion ;  beyond  that  limit,  the  compressive  strength  usually  ex- 
ceeds the  tensile  in  a  proportion  which  varies  greatly.    Copper 
and  other  non-ferrous  metals  are  rarely  used  in  the  form  of 
columns.     Should  it  be  necessary  to  so  use  them,  the  formu- 
las given  in  Part  II.  and  in  special  works  on  strength  of  ma- 
terials may  be  used,  substituting  the  proper  value,  C,  of  the 
modulus  for  compression. 

159.  The  Transverse  Strength,  or  the  resistance  of  any 
piece  to  bending,  is  determined  by  the  longitudinal  strength 


STRENGTH  OF  NON-FERROUS  METALS.  257 

of  the  metal,  both  in  tension  and  compression,  by  the  form 
of  the  piece,  and  by  its  absolute  dimensions.  When  this 
method  of  stress  affects  a  bar  of  metal,  there  is  called  into 
action  at  every  section  a  set  of  forces  resisting  flexure,  each 
acting  about  a  u  neutral  line "  at  which  the  forces  change 
sign.  If  a  bar  is  placed  in  the  testing  machine,  and  if,  while 
supporting  it  at  each  end,  the  machine  is  made  to  apply  a 
depressing  force  at  the  middle  of  the  piece,  the  upper  part  of 
the  bar  is  compressed,  and  the  lower  extended  ;  while  be- 
tween these  portions  of  strained  metal  is  a  plane  of  unstrained 
material,  whose  trace  on  the  vertical  plane  is  the  neutral  line. 
The  moments  of  the  forces  by  which  the  bar  resists  compres- 
sion above  and  extension  below  this  plane,  together  produce 
the  measured  resistance  to  flexure.  The  position  of  the  neu- 
tral plane  is  determined  by  the  relation  existing  between  the 
magnitudes  of  the  two  forms  of  resistance  ;  it  may  be  con- 
sidered as  always  at  the  middle  of  the  section,  within  the 
elastic  limit,  while  beyond  that  limit  it  approaches  that  side 
at  which  resistance  is  greatest  at  the  moment.  The  total 
resistance  to  flexure,  then,  is  measured  by  the  sum  of  these 
two  moments  of  resistance,  which  are  themselves  measured 
each  by  the  product  of  the  mean  resistance  of  the  strained 
parts  of  the  most  severely  loaded  cross  section  affected  by  it 
into  its  own  lever  arm. 

By  the  ordinary  theory,  and  its  resulting  equations,  the 
resistances  of  particles  to  compression  and  to  extension  are 
taken  proportional  to  their  distance  from  the  neutral  surface ; 
this  is  correct  up  to  that  limit  of  flexure  at  which  the  exte- 
rior sets  of  particles  on  the  one  side  or  on  the  other  are 
forced  beyond  the  elastic  limit.  With  absolutely  non-ductile 
materials,  or  materials  destitute  of  viscosity,  fracture  occurs 
at  this  point;  but,  with  nearly  all  of  the  metals  and  alloys  in 
common  use,  rupture  does  not  then  take  place.  The  exterior 
portions  of  the  mass  are  compressed  on  the  one  side,  offering 
more  and  more  resistance  nearly,  if  not  quite,  up  to  the  point 
of  actual  breaking,  which  breaking  may  only  occur  long  after 
passing  the  elastic  limit ;  on  the  other  side,  similar  sets  of 
particles  are  drawn  apart,  passing  the  elastic  limit  for  tension, 
17 


258    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 


and  then  resisting  the  stress  with  a  more  nearly  constant 
force,  "  flow  "  occurring  until  the  limit  of  that  flow  is  reached, 
and  rupture  takes  place. 

No  expressions  have  yet  been  derived  by  analysis,  and 
constants  determined  by  experiment,  which  enable  the  engi- 
neer to  express  by  an  equation  the  actual  method  of  varia- 
tion of  internal  resistances  with  variation  of  load  and  of  de- 
flection, for  all  materials  ;  but  sufficient  accuracy  is  usually 
obtained  for  practical  purposes  by  treating  the  case  in  the 
simplest  manner. 

160.  Methods  of  Distribution  of  Resistances,  in  cases  of 
flexure,  are  exhibited  in  the  accompanying  figures. 


FIG.  3.— FLEXED  ELASTIC  BEAM. 

In  MN,  the  material  being  perfectly  elastic  up  to  the 
limit  of  flexure,  the  stress  at  any  point  is  proportional  to  the 
area  of  the  element  strained,  to  the  maximum  elastic  resist- 
ance of  the  material,  and  to  the  distance  x  of  the  element 
from  the  neutral  plane  MON.  The  resistance  to  flexure 
within  the  range  of  perfect  elasticity  is,  therefore,  in  this 
case,  as  when  the  beam  is  ruptured,  at  that  limit  proportional 
to  the  breadth  of  the  piece  and  to  the  square  of  the  depth, 
where  the  section  is  rectangular. 

Where   a  metallic   beam    is  strained   beyond   the  elastic 

limit  at  any  part  of  its  sec- 
tion, the  stress  outside  that 
part  is  more  nearly  con- 
stant,  and  may  become 
equal  to  the  maximum  re- 

.r  IG.  4* 

sistance  of  the  material,  or 

nearly  so.     Thus,   in   Fig.  4,  the  law   of  resistance  changes 
at  a  and  is  no  longer  proportional  to  the  distance  of  the 


STRENGTH  OF  NON-FERROUS  METALS.  259 

strained  particles  from  the  neutral  plane,  but  has  the  maxi- 
mum  possible  value.     This   change  may  occur  abruptly,  as 
shown,  or  gradually,  making  the  shaded  parts  exhibiting  the 
magnitude  of  the  stress 
a  pair  of  parabolas  placed 
vertex  to  vertex.  Finally, 
with  all  perfectly  ductile  M' 
materials,  all  parts  of  the 
section    become    equally 
strained,  nearly  as  in  Fig.  5. 

161.  Theory  of  Rupture.* — In  the  usual  case,  in  which 
the  resistance  to  distortion  varies  from  a  maximum,  R,  at  the 
outer  surface  to  zero  on  the  neutral  plane,  as  in  brittle  ma- 
terials, we  have  for  the  elementary  area  dy  dx,  for  the  resist- 

/?  /? 

ance  —  y  per  unit  of  area,  and  —  y  dy  dx  on  the  area  dy  dx ; 

Ct  j  w, 

while  the  moment  of  resistance,  M,  on  that  part  of  the  whole 
section  which  lies  on  one  side  the  neutral  plane  is  obtained 
by  integration  from  that  line  to  the  most  strained  fibre  on 
that  side,  at  a  distance  dv  R  being  the  "  Modulus  of  Rupture  " : 


R  r 
aj 


*>.,  the  quotient  of  the  modulus  of  rupture  by  the  distance 
of  the  most  strained  fibre  from  the  neutral  line,  multiplied  by 
the  moment  of  inertia  of  the  section  considered. 

When  the  resistance,  after  passing  the  elastic  limit,  be- 
comes throughout  equal  to  the  maximum  R,  we  have  per 
unit  of  area,  a  resistance  R  dy  dx,  and  for  the  moment 


ft  tdl 
R\     ,  y  dy 

Jo  Jo 


=  M'. 


For  rectangular  beams,  when  the  neutral  line  may  be 
taken  at  the  middle  of  the  section,  as  with  non-ductile  ma- 
terials generally  for  the  first,  and  for  copper,  tin,  lead  and 

*  See  Wood's  "  Resistance  of  Materials  "  for  the  Theory  of  Resistance. 


260  MATERIALS  OF  ENGINEERING—  NON-FERROUS  METALS. 

other  substances   having  nearly  equal  values  of  T  and  C,  for 
the  second  case,  we  get,  for  the  two  cases  respectively  : 


(a)  M=\Rbd2\          (b)  M*  = 

b  being  the  breadth,  and  <^=  2*/r  the  total  depth  of  section. 

Thus,  assuming  the  same  value  for  ultimate  resistance  of 
cohesion,  the  ductile  substance  offers  one-half  greater  resist- 
ance than  the  non-ductile,  and  one-half  greater  resistance 
just  beyond  than  just  within  the  elastic  limit.  Hence,  also, 
it  can  only  be  expected  that  the  value  of  R  will  coincide  with 
the  resistance  to  direct  tension  or  direct  compression  in  rare 
cases.  It  is  evident  that  the  actual  value  of  R  may  be  com- 
pared with  the  values  of  T  and  C,  to  determine  to  what 
extent  the  case  approaches  that  giving  the  second  of  these 
equations. 

The  first  of  these  cases  is  that  which  it  has  been  custom- 
ary to  assume  as  applicable  in  all  cases.  Its  solution  evi- 
dently gives  results  differing  from  the  truth  on  the  right  side. 

Examining  the  equation,  it  is  seen  that  the  moment  of  re- 
sistance, M}  is  measured  by  the  product  of  the  "  modulus  "  of 

rupture,  R,  into  the  quantity  y2  dy  dx  divided  by  the  depth 
di  to  the  neutral  line,  or  as,  shown  by  M.  Navier,  to  the  axis 
through  the  centre  of  gravity.  The  quantity  y2  dy  dx, 

which  is  always  a  factor  in  this  expression,  is  the  "  moment 
of  inertia." 

The  data  to  be  here  given  are  experimentally  obtained 
figures,  derived  from  tests  of  pieces  of  rectangular  section  ; 
other  forms  will  be  considered  later. 

162.  Formulas  for  Transverse  Loading  are  deduced  in 
all  works  on  resistance  of  materials.  For  cases  of  rupture, 
when  the  beam  is  supported  at  the  ends  and  loaded  in  the 
middle,  for  rectangular  bars, 


-P/=  ]?Rbd*  ;  and  R  = 
4          6  2bd 


STRENGTH  OF  NON-FERROUS  METALS.  26l 

for  non-ductile  materials,  and  it  may  be  assumed,  in  all  cases 
in  the  engineer's  practice,  that  the  material  tested  is  in  prac- 
tice either  sufficiently  elastic  and  rigid  to  justify  the  use  of 
this  formula,  or  is  to  be  loaded  only  within  its  elastic  limit. 
Then  the  formulas  for  other  cases  become  : 

(i.)  Beam  fixed  at  one  end,  load  at  the  other  : 

Pl=~Rbd2-,       p=LRML. 
o  o         / 

(2.)  Same,  with  load  distributed  uniformly: 


(3.)  Beam  supported  at  ends,  loaded  at  middle  : 

Lpl=M,  P=2-R^. 

4  3        / 

(4.)  Same,  uniformly  loaded  : 

l-Wl=M;  »'=!»*£. 

(5.)  Beam  firmly  fixed  at  ends,  loaded  at  middle 
^-.jr;  P-*R». 

Same  determined  by  Barlow's  experiments  : 
I/y=J/;  P=R*£. 

O  / 

(6.)  Same  uniformly  loaded  : 


—  Wl-M\ 
12 


262  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

(7.)  Fixed  at  one  end,  supported  at  the  other,  load  at  the 
middle: 


All  of  these  equations  are,  of  course,  "homogeneous." 

Replacing  bd2  by  0.59^,  transforms  these  quotations  so 

as  to  apply  very  exactly  to  circular  sections. 

163.  The  Modulus  of  Rupture,   R,   being   obtained   by 

experiment    and  inserted    in  these  formulas,  the  maximum 

load  that  a  beam  will  support,  when  of  similar  shape  and  of 

that  material,  becomes  calculable. 

The   value   of   the  modulus  of  rupture  is  readily  deter- 

mined by  experiment  from  the  formula  : 


when  the  weight  of  the  beam,  W,  is  taken  into  account. 
When  the  dimensions  all  become  unity,  we  have,  neglecting 
W, 

P  —  3  p. 

2       ' 

that  is  to  say,  the  modulus  of  rupture  is  one  and  a  half  times 
the  load  which  would  break  a  bar  unity  in  length,  breadth 
and  depth,  supported  at  the  ends  and  loaded  in  the  middle. 
For  British  measures,  it  is  1  8  times  the  weight  that  would 
break  a  bar  so  loaded  if  one  foot  long,  and  one  inch  square 
in  section. 

Very  ductile  bars  bend  without  breaking.  The  correct 
modulus  of  rupture  in  these  cases,  therefore,  cannot  be  de- 
termined, and  it  is  necessary  to  assume  a  given  amount  of 
bending  as  equivalent  to  breaking  the  bar  or  rendering  it 
useless,  and  the  modulus  of  rupture  is  calculated  from  the 
load  causing  this  maximum  deflection,  to  afford  a  means  of 
comparing  the  transverse  strengths  of  all  bars  which  were 
tested. 


STRENGTH  OF  NON-FERROUS  METALS. 


263 


164.  The  Theory  of  Elastic  Resistance,  as  generally  ac- 
cepted, is  as  follows : 

In  figure  6,  which  represents  a  longitudinal  section  through 
a  loaded  beam,  let  £Fbe  the  neutral  line  extending  through- 
out   its   length.     Let  AB  and 
CD  be  consecutive   transverse 
sections  separated   by  the  dis- 
tance dx ;  C'D'  is  the  position 
of   C  when    swung   out   of   its 
original  place  by  the  action  of 
the  load  W,  and  its  intersection 
with  the  plane  AB  is  found  at 
R.     Then,  ab  being  the  original 
length  of   any  fibre   at    a   dis- 
tance Ob  —  yl  from  the  neutral  axis,  bc  —  \  will  be  its  elonga- 
tion, and  if  the  radius  of  curvature,  OR,  is  called  p,  we  have 

i  —ydx 

A___; 


A       C  C 

a 

—  b 

F 

E-  <5 

..'/ 

•o-  —  - 

9,0-1 

I 

FlG  6 


and   the   stress   on   any  fibre   of   the  area,  a  —  dy  dz,  since 


£iE::\idx9  will  be 
a 


and  the  moment  about  the  intersection  with  the  neutral  line 


is 


accordingly  as  the  fibre  is  above  or  below  that  line. 
The  total  moment  will  be 


E  (b  (d*  E  (b  \d2 

=±     \fdjd*  +  \          fdydz. 

P  Jo  Jo  P   Jo  Jo 


For  cases  in  which  the  section  is  symmetrical  about  the 
neutral  line 

El       E  [b  (+xd 
'=  —  =  -  y*dy  dzt 

P  PJoJ-kT/      ' 


., 

M 


264   MATERIALS   OF  ENGINEERING—  NON-FERROUS  METALS* 

in  which  integrals  b  is  the  breadth  of  section,  */,  and  d2  are 
the  depth  of  the  half  sections  above  and  below  EF,  and  d  is 
the  total  depth.  Also, 


The  value  of  p,  the  radius  of  curvature,  is  shown  in  works 
on  the  differential  calculus  to  be 


p=  ± 

dx* 
which  value  reduces  the  equation  for  M  —  PI,  as  in  Fig.  6,  to 


when   ~j  may,   as    is   probably    usually   the   case,  be   neg- 

CLsv 

lected. 

Inserting  the  value  of  M  in  terms  of  x,  we  have,  for  ex- 
ample, with  the  "  cantilever,"  or  beam  fixed  at  one  end, 
loaded  at  the  other,  origin  at  the  fixed  end  : 


, 

which,  being  integrated  once,  gives 


where  x  =  O,   --  =  O,  and  C—  O. 
Again  integrating,  and 


STRENGTH  OF  NON-FERROUS  METALS.  265 

in  which,  where  x  =  o,  y  =  O  and  C  =  O,  and  the  value  for 
deflection  at  x  =  /,  for  this  case  is 


D  - 


w 


as  already  given. 

For  uniform  loading, 


and 


All  usual  cases  are  developed  in  treatises  on  the  theory  of 
the  resistance  of  materials. 

The  elastic  resistance  to  flexure  is  of  greater  importance 
in  very  many  cases  than  the  ultimate  transverse  strength,  as 
pieces  are  in  machinery  almost  invariably,  and  in  other  struct- 
ures usually,  rendered  useless  when  the  change  of  form  ex- 
ceeds a  limit  which  is  generally  intended  to  be  well  within 
the  elastic  range. 

In  some  of  the  tables,  the  figures  in  the  column  headed 
"  Modulus  of  Elasticity,"  are  those  which  are  considered  the 
most  probable  moduli  within  the  elastic  limit,  or  which  most 
nearly  represent  the  relation  between  the  stresses  and  the 
distortions  within  that  limit. 

In  a  few  instances  the  apparent  modulus  at.  the  beginning 
of  the  test  is  much  smaller  than  it  soon  afterward  becomes; 
and  this  indicates  either  a  possible  error  or  the  existence  of 
internal  stress  at  this  part  of  the  test. 

In  general,  we  have,  within  the  elastic  limit, 


~ 


for  the  case  of  a  beam  fixed  at  one  end  and  loaded  at  the 
other. 


266    MATERIALS  OF  ENGINEERING—  NON-FERROUS  METALS. 

When  uniformly  loaded, 


~  8  El  '  /3 

For  beams  supported   at  the   ends,  these  equations    for 
single  and  distributed  loads  are 

i_PP_t 

"  ' 


48  £/  '  /3 


For  beams  fixed  at  the  ends,  we  have 

I    P/3  20oD£f 

D  —  -      -=-=:  ,  nearly  ;  P  =  --  n 

200  El  /3 


For  rectangular  beams, 


and  we  may  write  the  simplified   formula   for  a  beam  sup* 
ported  at  the  ends  and  loaded  in  the  middle, 


For  a  beam  fixed  at  one  end  and  loaded  at  the  other, 

\6aPl* 
M,    '' 

and,  when  uniformly  loaded,  the  t    o  cases  give 


and 


STRENGTH  OF  NOX-FERROUS  METALS.  267 

Where  the  length  is  measured  in  inches, 

i  1728 

a  =  — £,»  and  when  in  feet,  a  =    '       • 

165.  The  Torsional  Strength  and  elasticity  of  iron  and 
steel  have  been  less  thoroughly  investigated  than  either  of 
the  other  forms  of  resistance. 

The  moment  of  the  applied  force,  as  measured  by  the 
product  of  the  magnitude  of  that  force  into  the  length  of  its 
lever-arm,  at  each  instant  equilibrates  the  resistance,  and  the 
formula  for  elastic  resistance  becomes: 

r,       ,,      2ns  fri   „    , 
Fl  —  M  —  r3  dr. 


For  solid  cylinders, 

Fl=  M  =  1.5708^  =  0. 
For  hollow  cylinders, 

—  r 


=M=  i.  5708.9    -' 


, 

I 


where  F  is  the  applied  force,  /  its  lever-arm,  M  its  moment,  s 
the  resistance  of  the  material  on  the  unit  of  area,  or  the 
maximum  stress,  r0  and  rT  are  the  radii  of  the  shaft,  internal 
and  external,  and  d0  and  d^  are  the  diameters. 

The  angle  of  torsion  is  proportional  to  the  length  of  the 
part  twisted  and  to  the  torsional  moment.  The  formula 
giving  its  value  is 

2Mx  _  T>2M   x  _  Fix 

-~~'"~"~-        2~ 


x  being  the  length  of  the  part  twisted  ; 

I-/  Ttjr  ^^^i4  ns-l 

Fl=M=aC~  —=  Q.ooSC  -   -, 
32*  x 

in  which  formulas  C  is  the  coefficient  of  elasticity  of  torsion. 


268    MATERIALS  OF  ENGINEERING—  NON-FERROUS  METALS. 

166.  The  Strength  of  a  Metal  Shaft  depends  not  only 
on  the  magnitude  of  the  ultimate  resistance  of  the  mate- 
rial, but  upon  the  method  of  its  action.  With  brittle  mate- 
rials, fracture  must  occur  when  the  limit  of  resistance  of  the 
outer  layers  is  reached  ;  with  ductile  metals,  capable  of  flow, 
fracture  may  not  take  place  until  all,  or  nearly  all,  parts  of 
the  cross  section  have  been  highly  strained,  the  outer  portions 
yielding  by  flow  until  the  inner  parts  have  been  strained  to 
their  maximum. 

For  the  first  case,  we  have  for  the  area  of  each  elementary 

S  T 

ring,  2nr  dr,  for  the  stress  upon  it  s  =  —  —  ,  and  for  its  lever- 

'"i 

arm,  r. 
Then 


for  hollow  shafts,  and  when  r0  =  O,  d0  =  O,  as  for  solid  shafts, 
Fl=  M—  1.5708  slr^  =  0.196  s^*. 

To  obtain  the  diameter,  we  have  : 
For  solid  shafts, 


For  hollow  shafts, 

3 

d,  = 


In  these  formulas,  the  ultimate  resistance  may  be  taken 
as  already  given  for  tension,  and  the  factor  of  safety  should 
usually  be  large. 

When  the  material  is  capable  of  flow  to  such  an  extent 
that  the  whole  section  resists  with  maximum  effect,  we  have 


STRENGTH  OF  NON-FERROUS  METALS.  269 

the  elementary  area  as  before — 27trdr,  its  lever-arm  r,  and 
the  value  of  s  becomes  constant  and  equal  to  5,. 
Then 

Fl  =  27TS,  \rir*dr  =  -  ns1  (r?  -  r03)  =  0.26s,  (d,  -  d0  ), 

J  ro  3 

and  when  r0  =  O, 

Fl=  o. 


In  such  cases,  therefore,  the  strength  of  the  shaft  is  in- 
creased one-third  by  the  ductility  of  the  metal.*  It  is  uncer- 
tain to  what  extent  this  action  occurs,  and  it  is  still  more 
uncertain  to  what  extent  the  action  here  occurring  is  a  true 
shearing  action.  The  last  set  of  formulas,  above  deduced, 
are  rarely  used  by  the  engineer. 

When  the  section  is  square,  the  resistance  is  increased 
about  40  per  cent,  above  that  of  a  circular  section  having  a 
diameter  equal  to  the  side  of  the  square. 

The  real  condition  of  the  metal  under  stress  is  undoubt- 
edly always  intermediate  between  the  two  cases  above  taken, 
the  metal  near  the  centre  resisting  as  a  solid  shaft  strained 
within  the  elastic  limit  at  its  outer  bounding  surface,  while 
the  external  portion  acts  as  a  hollow  shaft  strained  through- 
out beyond  that  limit.  Assuming  the  latter  to  be  strained  to 
the  maximum  throughout,  and  taking  rl  r2  as  the  radii  of  the 
two  parts,  the  total  resistance  would  be- 


*  First  shown  by  Prof.  Jos.  Thomson  (Cam.  and  Dub.  Math.  Jour.,  Nov., 
1848;  Ency.  Brit.,  Art.  Elasticity,  pp.  798-9,  1883);  his  paper  was  not  dis- 
covered by  the  Author  until  he  had  himself  determined  the  facts  experimentally, 
had  reconstructed  the  theory  as  above,  and  had  applied  it,  further,  to  the  case  of 
bent  beams,  as  in  Art.  161,  and  in  Part  II.,  Arts.  262-3,  277. 


2/O  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

If  ae  and  ar  are  the  angles  of  torsion  at  the  elastic  limit  of 
the  piece  and  at  the  beginning  of  rupture  or  of  flow, 


and 


If  ae  =  ar,  M=  \7tsr*,  as  already  shown  for  brittle  sub- 
stances. When  ae  =  o,  as  in  absolutely  inelastic  materials, 
did  such  exist,  or  when  otr  =  oo ,  as  with  perfectly  ductile  sub- 
stances, M=  %7tsr3,  as  already  deduced  for  substances  capable 
of  unlimited  flow. 

When  the  torsional  moment  is  given,  the  diameter  of  a 
shaft  in  inches  is  given  by  Molesworth  as 


in  which 


d  —  diameter  in  inches. 
/  =  lever-arm  in  inches. 
P=.  twisting  effort  in  pounds. 


VALUES   OF  K. 


Wrought  iron 1,700 

Copper 380 

Tin 220 


Gun  bronze 460 

Brass 425 

Lead 170 


167.  The  Tenacity  of  Copper  varies  very  greatly  with 
physical  and  chemical  modifications  of  structure  and  com- 
position. In  the  ingot,  if  pure,  it  is  generally  stronger  than 
in  masses  re-cast,  as  it  is  peculiarly  liable  to  injury  by  the 
absorption  of  oxygen,  the  production  of  "  blow-holes,"  and 
the  formation  of  oxide.  Rolled  and  forged  copper  are 


STRENGTH  OF  NON-FERROUS  METALS. 


271 


stronger  than  ingot  metal.  They  are  made  from  well-fluxed 
ingots  and  are  strengthened,  like  all  rolled  or  forged  metals, 
by  working.  Drawn  copper  is  still  stronger,  and  its  strength 
increases  as  the  wire  is  smaller. 

Major  Wade  *  found  the  tenacity  of  Lake  Superior  cast 
copper  to  range  from  22,000  to  nearly  28,000  pounds  per 
square  inch  (1,547  to  1,968  kilog.  per  sq.  cm.),  averaging  above 
24,000  pounds  (1,705  kilogs.).  Egleston  gives  the  tenacity  of 
both  Lake  Superior  and  Ore  Knob  (N.  C.)  copper  as  above, 
30,000  pounds  per  square  inch  (2,109  kgs.  per  sq.  cm.). 

Anderson  f  gives  the  figures  for  the  tenacity  of  copper, 
which,  in  round  numbers,  are  as  below — ordinary  copper  is 
compared  with  that  fluxed  with  phosphorus : 

TABLE  XXXIV. 

TENACITY   OF   COPPER. 


PHOS. 

TENACITY,    T. 

Lbs.  per 
sq.  in. 

Kilog.  per 
sq.  cm. 

34000 
19,000 
25,000 
38,000 
45,ooo 
48,000 
50,000 

2,390 
1,336 
1,758 
2,671 
3,164 
3.374 
3,515 

cast  

forged     •• 

O.OI5 
0.02 
O.O3 
O.O4 

« 

t( 

The  effect  of  fluxing  with  phosphorus  is  here  very  plainly 
shown  and  amounts  to  an  average  increase  of  tenacity  of  4,000 
pounds  per  square  inch  (2,812  kilogs.  per  sq.  cm.)  for  each 
one  per  cent,  added  up  to  four  per  cent. 

168.  Cast  Copper. — The  following  are  the  records  of 
tests,  made  by  the  Author,  of  ingot  copper  and  of  copper 
castings  made  direct  from  re-melted  ingot: 


*  Metals  for  Cannon,  1856. 
f  Strength  of  Materials. 


2/2   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

TABLE   XXXV. 

TESTS   OF   INGOT   COPPER. 

No.  654  a  ;  length  5",  diameter  0.798"  ;  sound. 


LOAD  J    LBS. 

EXTENSION,    INCH. 

LOAD  ;    LBS. 

EXTENSION,  INCH. 

500 

O.OOOg 

7,000 

0.627 

1,000 

0.0038 

8,000 

0.941 

2,OOO 

O.OOSg 

120 

o  .  0964 

3,000 

0.0137 

9,OOO 

0.1507 

4,000 

O.O2O5 

IO,OOO 

0.2122 

I2O 

0.0089 

120 

O.2OO9 

5,000 

O.O279 

I2,OOO 

0.3686 

6,000 

0.0324 

1  2O 

0-3551 

1  20 

0.402 

13,000 

broke. 

Tenacity  26,000  Ibs.      per  sq.  inch,  original  area. 

1,828  kilogs.  "    "    cm. 
"         30,398  Ibs.        "     "    inch,  fractured. 
"  2,137  kilogs.  "     "    cm. 


No.  654  b,  same  as  above. 


LOAD. 

EXTENSION,  INCH. 

LOAD. 

EXTENSION,  INCH. 

500 

0.0004 

IO,OOO 

0.1388 

1,000 

O.OO32 

I2O 

0.1317 

4,000 

O.O2OI 

T  2,OOO 

O.3O2O 

1  20 

0.0037 

120 

0.2933 

7,000 

0.0485 

14,910 

broke. 

Tenacity  29,820  Ibs.      per  sq.  inch,  original  area. 

2,096  kilogs.  "    "    cm. 
"         36,217  Ibs.         "     "    inch,  fractured. 
"  2,546  kilogs.  "    "    cm.  ' 


169.  Tests  of  Copper. — The  methods  of  test  adopted 
by  the  Author  in  testing  these  materials  are  also  illustrated 
in  the  table  of  results  which  follow.  The  figures  given  ex- 
ceed those  obtained  from  similar  metal  by  Major  Wade. 


STRENGTH  OF  NON-FERROUS  METALS. 


2/3 


These  records  are  taken  from  the  records  of  tests  made 
for  the  Committee  on  Alloys  of  the  U.  S.  Board. 

The  tests  were  made  on  bars  cast  from  re-melted  ingot 
copper. 


TABLE  XXXVI. 


TESTS  OF   CAST  COPPER. 


No.  30  A.— Material :  Lake  Superior  copper,  cast  in  iron  mould.— Dimensions  :  Length,  5" 
(12.7  cm.)  j  diameter,  0.798"  (2  cm.). 


H 

10 

j,  . 

H 

MI 

, 

1 

Z 

§u 

< 

•     2 

-  -  K 

-   1 

D 

^ 

2  O  O 

H  z 

-  - 

H  S 

||S 

ii 

11 

ft 

Q 

a 

z  ** 

£  2*  ^* 

Q 

Q 

z  - 

Z  ^  ^ 

1 

M 

H 

| 

s 

3 

H 

Pounds. 

Pounds. 

Inch. 

Pounds. 

Pounds. 

Inch. 

400 

800 

0.0004 

.00008 

11,000 

22,000 

0.1605 

.03210 

1,000 

2,000 

O.OOII 

.00022 

12,200 

24,400 

0.2191 

.04382 

2  COO 

4,000 

0.0022 

.00044 

14,000 

28,000 

0.3258 

.06516 

4,000 

6,000 

8,000 

12,000 

O.OC27 
0.0032 

.00054 
.00064 

270 
14.400 

540 
28,800 

Set  0.3155 
0.3448 

^8-6" 

6,400 
6,800 

7,200 

12,800 

13,600 

14,400 

O.C052 
0.0083 
0.0132 

.00104 
.00166 
.00264 

14,600 

Broke  y& 
A  end.     F 

29,200 
st  as  readir 
ractured  se 

0.3760            .07520 
g  was  taken  #  inch  from 
ction  distorted  from  cir- 

8,000 

8,800 
9,600 
9,800 
250 

10,200 

16,000 
17,600 
19,200 
19,^00 
500 
20,400 

0.0358 
0.0642 
0.0942 
0.1073 

Set  0.0951 
0.1218 

.0^.716 
.01284 
.01884 
.02146 

cular  form.    Three  diameters  measured  0.737 
inch,  0.725  inch,  and  0.732  inch. 
Tenacity  per  square  inch  original  section, 
29.200  pounds  (2,053  kilogs.  per  sq.  cm). 
Tenacity  per  square  inch  fractured  section, 
34,790  pounds  (2,446  kilogs.  per  sq.  cm.). 

02436 

No.  525  a  ;  length,  6"  ;  diameter,  0.798"  ;  sound  casting. 


NO.    LBS.;  LOAD. 

EXTENSION,   INCH.    1 

NO.    I.BS.;   LOAD. 

EXTENSION,  INCH. 

3,470 

0.01 

5,900 

0.07 

4,240 

0.02 

6,780 

0.12 

4,920 

0.03 

7,220 

0.16 

5,350 

0.04 

7,270 

broke. 

Tenacity  14,540  Ibs.      per  sq.  inch. 
"          1,022  kilogs.   "    "   cm. 


274  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
No.  525  b  ;    size  as  above  ;   sound. 


NO.    LBS.;    LOAD. 

EXTENSION,    INCH. 

NO.    LBS.  J   LOAD. 

EXTENSION,  INCH. 

4,OOO 

0.01 

8,100 

0.23 

4,900 

O.O2 

g.OOO 

0.30 

5,100 

0.03 

IO,OOO 

0.40 

6,2OO 

O.II 

10,220 

broke  . 

7,550 

0.17 

Tenacity,  20,646  Ibs.       per  sq.  inch. 
1,451  kilogs.    "    '4  cm. 

No.  57  B. — Material :  Copper  cast  in  iron  mould. — Dimensions  :  Length,  5"  (12.7  cm.) ; 
diameter,  0.798"  (2  cm.). 


W 

10 

z 

2£x 

W 

K 

< 

10 

Z 

2gx 

D 

§• 

<y,     O     O 

D 

Z    ' 

2  O  O 

O*    • 

a 

Q   [t,   Z 

%  -' 

o  a 

2  o  w 

K  5 

HS 

H  °  3 

«s 

HX 

gs 

Q 

III 

£2 

Q 

<  u 

0  Z 

<  55  . 

OS" 

z  5  5 

< 

o 

EH' 

0 

L| 

O  2]  S 

s 

ij 

H 

H 

w*" 

3 

,_] 

% 

H 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

1,000 

0.0004 

.0001 

17,000 

0.0779 

.... 

.0156 

2,000 

0.0032 



.0006 

i8,ooj 

0.0951 

.0190 

3,000 

0.0064 

.0013 

19,000 

0.1142 

.0228 

4,000 

0.0093 



.0019 

20,000 

0.1388 

.02/8 

5,000 

0.0116 

.0023 

240 



o  1317 

6,000 

0.0144 

.0029 

21,000               O.I7C2 



.0340 

7,000 

0.0170 



.0034 

22,OOO 

0.2028 

.0406 

8,000 

0.0201 

.0040 

23,000 

0.2444 

.0489 

240 

o  0037 

24,000 

0.3020 



.0604 

9,000 

0.0227 

.0045 

240 



0.2933 

10,000 

0.0263 



•  o°53 

25,0:0 

0.3585 

.0717 

11,000 

12,000 

0.0321 
0.0371 

:  :::: 

.0064 
.0074 

26,000 
29,820 

Measuring  apparatus  slipped. 
Broke  2  inches  from  B  end. 

240 

o  0253 

Diameter  of  fractured  section,  0.72}  inch. 

13,000 
14,000 
15,000  • 
16,000 

0.0428 
0.0485 
0.0554 
0.0652 

!oo86 
.0097 

.0111 

.0130 

Tenacity  per  square  inch,  original  section, 
29,820  pounds  (2,096  kilogs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  section, 
36,217  pounds  (2,546  kilogs.  per  sq.  cm.). 

240 

o  0583 

Records  of  tests  of  cast  copper,  as  here  given  above,  ex- 
hibit the  variable  quality  of  this  material,  due  to  its  absorp- 
tion of  oxygen. 

These  tables  illustrate  the  method  of  variation  of  resist- 
ance with  deformation  and  with  increasing  load,  and  exhibit 
the  figures  obtained  in  a  form  which  admits  of  the  production 
of  a  strain-diagram. 

The  method  of  variation  of  the  diameter  of  a  test-piece, 
in  tension,  along  the  stretched  portion  is  seen  in  the  follow- 


STRENGTH  OF  NON-FERROUS  METALS. 


275 


ing  record  of  test  of  copper  fluxed  with  fluor-spar,  a  flux 
which  was  expected  to  give  much  better  results  than  were  in 
this  case  actually  obtained. 


TABLE   XXXVII. 


TEST   OF   CAST   COPPER   (FLUXED   WITH    FLUOR-SPAR). 

No.  51  B.— Material :   Copper,  cast  in  hot  iron  mould,  fluxed  with  fluor-spar.— Dimensions : 
Length,  6.19"  (15.5  cm.) ;  diameter,  0.798"  (2  cm.). 


LOAD  PER  SQUARE 
INCH. 

ELONGATION  IN 
6.19  INCHES. 

\ 

ELONGATION  IN 
PAKTS  OF  ORIG- 
INAL LENGTH. 

Diameter  of  fractured  section,  0.763  inch. 
Tenacity  per  square  inch,  original  section 
pounds  (1,437  kilogs.  per  sq.  cm.). 
Tenacity    per    square    inch,    fractured    s 
22.353  pounds  (1571  kilogs,  per  sq.  cm.). 
The  following  measurements  were  made 
diameter  of  the  piece  after  breaking  : 

At  fractured  section  ... 

,  20,440 
action, 
of  the 

Inch. 
0.763 

::$ 

o.7d6 

0.765 
0.760 

l:$i 

0.768 
0.774 

Pounds. 
8,000 
9,800 
io,coo 
11,400 
12,400 
15,100 
16,200 
17,040 
iS.coo 
19,400 

20,000 
O 
20,400 
20,440 

Broke  at  E 

Inch. 

O.OI 
O.O2 
0.03 
.       0.07 

O.II 

0.17 
0.23 

0.26 

0.30 

0.36 
0.40 

0.44 
0.46 
>end. 

Inch. 

.0016 
.0032 
.0048 
.0113 
.OI71 
.C275 
•  C372 

.C258 

.0485 
.0^81 
,o<46 

.0710 
•0743 



)4  inch  from  fractured  section 

i  inch  from  fractured  section        



2  inrhes  from  fractured  section 

3  inches  from  fractured  section  

4  inches  from  fractured  section  

4^  inches  from  fractured  section  

5  inches  from  fractured  section  

6  inches  irom  iraciured  section 

6>2  mcnes  from  fractured  section  

0.40 

The  importance  of  effective  fluxing  and  of  skill  and  care 
in  melting  and  casting  copper,  are  well  shown  by  a  compari- 
son of  the  figures  given  above  for  ingot  copper  with  those 
obtained  for  the  several  re-cast  samples,  and  even  better  by 
contrasting  the  figures  obtained  for  the  latter  with  those 
to  be  given  for  rolled  and  drawn  copper,  which  may  be  taken 
to  represent  the  most  perfect  attainable  soundness. 

Rolled  Copper  as  tested  by  the  Author,  in  bars  pur- 
chased in  the  market,  had  a  tenacity  of  32,000  pounds  per 
square  inch  and  reduced  in  section  40  per  cent.  Two  samples 
from  the  same  bar  gave  the  same  figure.  Rolled  copper  has 
been  tested  by  a  committee  of  the  Franklin  Institute  *  who 

*  Journal  of  the  Franklin  Institute,  1837. 


276  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

found  that  the  mean  of  over  60  experiments  gave  a  tenacity 
of  very  nearly  33,000  pounds  per  square  inch  (2,399  kilogs.  per 
sq.  cm.),  the  variations  amounting  to  from  2  to  5  per  cent. 

Rolled  copper,  tested  by  Bauschinger,  exhibited  tenacities 
varying  from  29,000  to  32,000  pounds  per  square  inch  (2,663 
to  2250  kilogs.  per  sq.  cm.),  with  a  reduction  of  section,  at 
fracture,  of  30  to  45  per  cent. 

Several  authorities  agree  on  nearly  the  following  figures 
for  various  commercial  forms  of  copper: 

TABLE  XXXVIII. 

TENACITY  OF   COMMERCIAL   FORMS   OF   COPPER. 


LBS.    PER  SQ. 
INCH. 

KILOGS.  PER  SQ. 
CM. 

Copper  cast                     .  . 

24  ooo 

I  434 

'  '       forged     .                                            .... 

M.ooo 

2,1^7 

"        bolt  

36,000 

2,151 

"       sheet  . 

36,000 

2,1^1 

62,000 

4,2^2 

Major  Wade  found  the  tenacity  of  "  L.  S."  copper  used  in 
making  U.  S.  ordnance  to  be  from  24,000  to  25,000  pounds 
per  square  inch  (1,688  to  1,758  kilogs.  per  sq.  cm.),  and  that  of 
other  brands  to  be  between  20,000  and  21,000  (1,463  kilogs.), 
increasing  a  little  with  hammering.  The  density  varied 
between  8.523  and  8.757,  the  higher  figures  accompanying, 
usually,  high  values  of  T. 

According  to  Trautwine,  the  strength  of  cast  copper 
varies  from  18,000  to  30,000  pounds  (1,265  to  2,109  kilogs.),  a 
range  fully  confirmed,  as  above,  by  the  experiments  of  the 
Author.  Bolt  copper  ranges  from  25,000  to  40,000  pounds 
per  square  inch  (1,758  to  2,812  kilogs.  per  sq.  cm.),  and  wire 
is  the  stronger  as  it  is  drawn  finer  and  harder,  to  an  extent 
not  yet  well  settled  by  experiment. 

Wertheim  obtained   for  the  tenacity  of  hard  wire  4,100 


STRENGTH  OF  NON-FERROUS  METALS. 


277 


kilogs.  per  square  centimetre  of  section  (58,250  pounds  per 
sq.  in.),  with  an  elongation  of  0.0033,  and  for  the  same  wire, 
annealed,  3,160  kilogs.  (44,900  pounds),  with  an  extension  of 
0.003. 

Copper  steam  pipes  are  sometimes  given  a  thickness  • 

/  =  0.00148  n  d  +  0.16,*  nearly  ; 
or,  according  to  some  authorities,f 

/  =  0.0001  dp  +  0.125, 

when  t  is  the  thickness  in  inches,  n  the  number  of  atmospheres 
pressure,  d  the  inner  diameter,  and  /  the  pressure  in  pounds 
per  square  inch.  Feed  pipes  are  a  little  heavier. 

170,  Shearing  Stresses  for  Copper  and  sheet  brass  are 
given  by  the  Ordnance  Bureau  of  the  United  States  War 
Department  \  as  below : 

TABLE  XXXIX. 

SHEARING   OF   COPPER   AND    BRASS. 
Punching. 


DIAME- 
TER OF 
PUNCH. 

PRESSURES. 

THICK- 
NESS OF 
SHEET. 

PRESSURES. 

Circ.  hole  i  in.  diam. 

IRON. 

Brass, 
.os  inch 
thick. 

Copper, 
.  15  inch 
thick. 

Iron, 
.105  inch 
thick. 

Copper. 

Brass. 

Thick- 
ness. 

Pressure, 
Circ.  hole 
i  in.  diam. 

In. 
1.5 

1-375 
1.25 

I.O 

.Q 

.8 

:i 

•5 
•  4 
•  3 

.2 

Lbs. 

8,475 
7.723 
6,980 
5,450 
5.092 
4.332 
5.772 
3,267 
2,635 
2,:83 
-,673 

1,110 

Lbs. 
i5,996 
14,570 
13-275 
",073 
9,788 
8,580 
7,827 
6,706 
5,507 
4,585 
3,435 
2,240 

Lbs. 
23,273 
21*445 
19,682 
16,535 
M,778 
12,602 
11,468 
9,772 
7,9i6 
6,660 
4,970 
3-333 

In. 

•  3 
.205 
•  150 
.100 

Lbs. 

21,248 
15,542 
11,088 
8,461 

Lbs. 

In. 
.615 
•  565 
.510 
•  445 
.404 
.358 
.283 
•245 
.183 
•  145 
.104 
•  057 

Lbs. 

82,871 
76,962 
69,984 
62,591 
57,623 
51,382 
40,486 
35,7" 
27,978 
22,213 
i6,533 
9>452 

.050 
•045 
.041 
•°34 
.032 
.028 

.022 

3,646 
3,362 

2,538 

2,212 

1.544 

5.448 
4,997 
3,73° 
3,54° 
2,964 
2,448 

*  Ordnance  Manual.  f  Seaton  on  Marine  Engineering. 

Ordnance  Manual. 


278  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


SHEARING. 

Angle  formed  by  shear-blades,  3  degrees. 
Sheet  Metals. 


IRON. 

COPPER. 

BRASS. 

STEEL,  PUDDLED. 

Thickness. 

Pressure. 

Thickness. 

Pressure. 

Thickness. 

Pressure. 

Thickness. 

Pressure. 

In. 

I.O* 

.615 
.510 
.404 
.283 
.183 
.104 
.057 

Lbs. 
144,000 

53,440 
39,*5° 
25,970 
i5,7!5 
10,390 
4,200 
2.180 

In. 

.207 
.238 
.204 
.150 
.09 
.064 
•  05 

.02 

Lbs. 

11,196 
6,007 
4,820 

3,676 

2,200 
I,  OO6 

552 

"3 

In. 

05 
042 
035 
025 
024 

Lbs. 

54° 
423 
313 
220 

200 

In. 

24 
24 

Lbs. 

I4,020t 

14,9301: 

Bolts. 


IRON. 

COPPER. 

BRASS. 

Diameter. 

Pressure. 

Diameter. 

Pressure. 

Diameter. 

Pressure. 

Diameter. 

Pressure. 

In. 

Lbs. 

In. 

Lbs. 

In. 

Lbs. 

In. 

Lbs. 

1.142 

35-410 

.697 

13,979 

•943 

18,460 

I.  IIO 

29,790 

1.040 

3°,7°7 

.585 

J°,593 

.906 

13,872 

.905 

22,386 

•  945 

24,057 

•447 

5,543 

•775 

11,310 

•  779 

17,976 

.812 

19,688 

.320 

3W3 

•  635 

8,218 

.648 

11,648 

The  shearing  resistance  of  copper  is  usually  given  in  office 
hand-books  as  from  22,000  to  30,000  pounds  per  square  inch 
(1,420  to  2,109  kilogs.  per  sq.  cm.).  Its  value  may  be  taken  as 
the  same  as  in  tension  and  as  subject  to  the  same  variations. 

The  work  done  in  shearing  copper  is,  according  to  Has- 
well,  measured,  for  punched  holes,  by 

W=  96,000  dt, 

in  which    W  is  the  work  in  foot-pounds,  d  the  diameter  of 
the  hole,  and  t  the  thickness  of  the  sheet  in  inches. 

171.  Resistance  to  Compression  varies  with  copper,  as 
with  all  ductile  and  malleable  metals,  more  with  variation  of 
form  of  test-piece  and  method  of  application  of  the  stress 
than  with  the  ordinary  modifications  of  composition  and  of 
form  produced  in  manufacture,  as  ingots,  sheets,  rods,  bolts, 

*  The  cutters  were  parallel  ;  the  bar  3  inches  wide. 
f  With  oil.  %  Without  oil. 


STRENGTH  OF  NON-FERROUS  METALS. 

etc.  The  application  of  a  crushing  force  to  a  test-piece  of 
standard  size  and  proportions  first  reduces  it  to  the  barrel- 
form,  then  to  that  of  a  flat  cheese-shaped  mass,  and  finally  to 
a  sheet  of  which  the  total  resistance  to  compression  increases 
indefinitely  as  its  area  becomes  greater  by  flow.  The  com- 
pression stress  thus  increases  from  about  that  required  to  pro- 
duce rupture  by  tension  to  that  demanded  to  produce  free 
flow  when  the  intensity  of  the  stress  is  a  maximum ;  and  its 
total  amount  is  limited  only  by  the  area  of  the  sheet  pro- 
duced. The  intensity,  C,  of  resistance  to  compression  is 
usually  incorrectly  stated,  without  limitation,  as  about  100,000 
pounds  per  square  inch  (7,030  kilogs.  per  sq.  cm.)  for  rolled  or 
forged,  and  120,000  pounds  (8,436  kilogs.)  for  cast  copper. 
The  results  of  experiments  of  the  Author,  presently  to  be 
given,  indicate  that  good  cast  copper,  in  cylinders  of  three 
diameters  length,  will  exhibit  a  resistance  which  may  usually 
te  reckoned  up  to  a  compression  of  one-half  or  more,  as 


VT 

C=  145,000  y     '  nearly, 
Cm  =  1 0,000 1/  e'  nearly, 


where  C  and  Cm  are  the  resistance  to  compression  in  British 
and  metric  measures,  and  e  is  the  compression  in  unity  of 
length,  the  resistance  being  reckoned  per  unit  of  original  sec- 
tion. But  the  volume  of  the  piece  remaining  practically  un- 
altered, the  section  is  increased  very  nearly  in  proportion  to 
the  compression,  and  the  resistance  will  thus  become 


f7- 


C*  =  72,000 A/     '  nearly, 


Cm  =    5>oo°  4/    '  nearly, 
when  reckoned  per  unit  of  area  of  section  actually,  at  the 


280  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


moment,  under  compression.  Thus,  for  good  cast  copper, 
the  intensity  of  pressure  producing  flow  may  be  taken  as  not 
far  from  75,000  pounds  per  square  inch  (5,270  kilogs.  per  sq. 
cm.). 

Cast  copper  under  compression  gives  the  detailed  results 
exhibited  in  the  next  tables,  as  obtained  by  the  Author  for 
the  U.  S.  Board. 

TABLE   XL. 

TESTS  BY  COMPRESSIVE  STRESS. 
CAST  COPPER. 

No.  3o.— Material :  Lake  Superior  copper,  cast  in  iron  mould.— Dimensions  :  Length,  2" 
(5.08  cm.) ;  diameter,  0.625"  (x-6  cm.). 


W 
K 

S6  - 

w 

K 

S6-- 

< 

. 

D 

^        Q        H 

• 

5 

^  O  \*\ 

1 

|g 

0  b.  Z 

35  o  w 

1 

|g 

|o§ 

Q 

s 

Q 

I<I 

Q 

S 

s 

O 

K  K  J 

3 

8 

O 

8"' 

3 

8 

3 

Q    B.   M 

U 

j 

Pounds. 

Inch. 

Pounds. 

Pounds. 

Inch. 

Pounds. 

500 

0.003 

1,630 

.OOI5 

12,000 

o.  162 

39,114 

.O8l0 

1,000 

0.005 

3,259 

-0025 

13,000 

0.205 

42,373 

.1025 

2,000 

0.008 

6,519 

.0040 

14,000 

0.251 

45,633 

•1255 

3,000 

O.OII 

9,778 

•0055 

15,000 

0.294 

48,892 

.1470 

4,000 

0.014 

13,038 

.0070 

16,000 

0-337 

52,1:52 

.1685 

5,000 

0.018 

16,297 

.0090 

18,000 

0.422 

§",671 

.2IIO 

6,000 

0.021 

19,557 

.0105 

20,000 

o  510 

,190 

.2550 

7,000 

O.O26 

22,816 

.0130 

21,000 

0-559 

,449 

-2795 

8,000 

0.035 

26,076 

•0175 

22,OOO 

0.642 

71,709      1         .3210 

9,000 
10,000 

0.051 
0.080 

29,335 
32,595 

.0255 
,0400 

Piece  removed  slightly  bent. 
Surface  wrinkled. 

11,000 

O.Iig 

35,854 

•0595 

No.  51  B. — Material :  Cast  copper. 


u 

K 

2      ' 

U 

2  0 

^ 

<y 

fc  o  S 

SB 

1 

zog 

° 

t/> 

1/3  as 

g  h  Z 

o 

w  a 

£  b  2 

S 

S  2 

W  a;  J 

u 

gz 

tS  w  J 

M 

K 

3 

£ 

Q 

g  <  2 

9 

g 

Q 

s  5  z 

3 

8 

3 

8"" 

3 

8 

O 
J 

8"M 

Pounds. 

Inch. 

Pounds. 

Pounds. 

Inch. 

Pounds. 

150 

.0000 



20,000 

.6461 

65,188 

•323° 

4,000 

.0006 

13,038 

.0023 

22,000 

.7295 

71,709 

•3647 

6,000 

.0089 

19,557 

.0044 

24,OOO 

.7936 

78,228 

.3968 

8,000 

•  0573 

26,075 

.0286 

26,000 

.8619 

84,747 

•43°9 

0,000 

.1560 

32,595 

.0780 

28,000 

.9258 

91,266 

.4679 

2,000 

.2568 

39,TI4 

.1284 

30,000 

.9783 

97,785 

.4891 

4,000 

.3602 

45,633 

.1801 

32,000 

1.0308 

104,303 

•5*54 

6,000 
8,000 

.4489 
•  55" 

52,152 
58,671 

.2244 
.2756 

Specimen  did    not    show  any  cracks,  but 
merely  flattened  down. 

STRENGTH  OF  NON-FERROUS  METALS.  28 1 

Both  are  tests  of  cast  copper,  and  their  difference  illustrates 
well  its  variability  in  quality  as  ordinarily  cast.  With  proper 
fluxing  and  protection  from  oxidation  and  absorption  of  air, 
the  metal  should  give  a  uniform  and  maximum  resistance. 

Rolled  Copper,  according  to  Trautwine,  is  compressed  ^jth 
by  a  load  of  103,000  pounds  per  square  inch  (7,241  kilogs.  per 
sq.  cm.).  Its  maximum  strength  in  this  direction  is  not  far 
from  that  of  cast  copper,  as  above,  although  its  resistance 
rises  more  rapidly  as  pressure  is  applied  and  compression 
produced. 

172.  The  Compression  of  Rolled  Copper  by  Impact 
has  been  determined  by  the  Author  while  investigating  the 
efficiency  of  "  drop-presses,"  such  as  are  used  in  making 
"  drop-forgings." 

Two  drop-hammers  of  each  of  two  kinds  were  used  in 
making  the  comparison,  weighing  with  dies  about  nine 
hundred  and  about  three  hundred  pounds  respectively,  plain. 
They  were  adjusted  to  fall  twenty-eight  inches.  The  lost 
work  was  from  10  to  30  per  cent. 

The  gauges  used  in  measuring  the  work  done  by  the 
hammers  were  cylinders  of  pure  merchant  copper,  prepared 
for  the  purpose.  They  measured  : 

Size   No.    i. .    ....   2j^  inches  long l^  inches   diameter. 

"         "        2 2  "  "     I 

"       "     3 1%      "          "    %       " 

Of  these,  a  considerable  number  were  prepared  and 
divided  into  three  sets ;  one  for  use  with  each  kind  of  hammer, 
and  one  for  testing  and  standardizing  in  the  testing  machine. 
The  work  done  by  crushing  the  standards  in  the  testing 
machine,  to  the  same  extent  that  companion  specimens  were 
crushed  under  the  hammers,  gave  a  measure  of  the  action  of 
the  latter,  and  permitted  a  fair  comparison  to  be  made.  The 
amount  of  work  done  in  the  slowly-acting  testing  machine, 
in  producing  a  given  compression,  is  somewhat  less  than 
where  the  same  effect  is  suddenly  produced,  as  by  a  falling 
weight ;  but  this  difference  is  not  great  and,  if  it  could  be 


282   MATERIALS  OF  ENGINEERING—  NOX-FERRO US  METALS. 


determined  and  introduced,  would  increase  the  figure  here 
given  for  efficiency. 

The  results  of  the  experiments  thus  made  are  exhibited 
in  the  accompanying  table,  and  are  also  shown  in  the  diagram, 
Fig.  7.  The  final  results  are  given  in  foot-pounds  of  work  per 
pound  of  hammer,  and  the  unavoidable  differences  in  size  are 
thus  eliminated.  The  modulus  of  resistance  to  compression 
is  also  given. 

TABLE   XLI. 

TESTS  OF  COPPER  BY  IMPACT. 


WORK   OF   THE   DROP-HAMMER. 

WEIGHT   OF   DROP. 

903  Ibs. 

319  Ibs. 

SIZE   OF   COPPER 
CYLINDER. 

2^"xi4"diam-       i"  x  2" 
No.    I.               No.  2- 

1 

l"  X  2"                  |"  X  1^" 

No.  2.              No.  3. 

Area  in  square  inches"! 
under    compression  ( 
curves. 
(See  plate.) 

AD  E                   A  H  I 
45-23                    45-26 
Average,  45.34. 

AN  O                AR  S 
13-75                  T3-76 
Average,  i3-75i- 

Reduced  to  work  done,  ) 
or  inch  pounds.         j 

22,715                    22,630 
Average,  22,672. 

6,875                      6,880 
Average,  6,877. 

Ditto  in  foot  pounds.  .  .  . 

Average,  1,884. 

Average,  576. 

Work  done  per  pound  ) 
of    drop    in     inch  >• 
pounds.                       ) 

Average,  25.10 

Average,   21.56 

Ditto  in  foot  pounds.  ... 

Average,  2.09 

Average,  1  .  8 

Final      resistance      to  ) 
compression.             \ 

70,000  Ibs. 
31,751   kilogs. 

35.000  Ibs. 
15,876  kilogs. 

The  final  resistance  to  compression  in  the  testing  machine 
was  very  nearly  25,000  pounds  per  square  inch  (1,760  kilogs. 
per  sq.  cm.).  The  method  of  variation  of  resistance  is  well 
shown  in  the  accompanying  diagram,  in  which  the  compres- 
sion, in  inches,  is  measured  by  abscissas,  and  the  total  corre- 
sponding load  in  pounds,  by  ordinates.  The  curves  are  nearly 
cubic  parabolas. 


\ 


> 


\ 


\ 


K 

W       c 

a    S 


8 


Q  ;= 

J  * 

c^  I 

OC  n 

fe  ! 

z  1 

2  1 

S  i 

£  ui 


s      e 

S       £• 


•-  s  -- 


-'   9    «! 

a:    z    oc 

<    <    < 


\\ 


'    I 


284  MATERIALS  OF  ENGINEERING—  NON-FERROUS  METALS. 

The  effect  of  impact  on  the  tough  metals  having  no 
definite  limit  of  elasticity  is  modified  by  the  velocity  of  the 
striking  mass,  and  by  the  inertia  of  the  piece  attacked,  to  an 
extent,  as  yet,  not  fully  determined.  The  experiments  of 
Kick  indicate  a  considerable  increase  of  total  work  of  resis- 
tance, when  the  piece  is  deformed  in  this  manner,  over  that 
noted  when  the  compression  is  produced  slowly  by  steady 
pressure.  The  experiments  of  the  Author  also  indicate  that 
this  work  is  the  greater,  with  soft  and  malleable  metals,  as 
the  velocity  of  action  is  increased.  The  real  efficiency  of  the 
press,  as  above,  is  thus  probably  somewhat  greater  than  the 
figures  obtained  would  indicate. 

In  the  preceding  figure,  the  areas  cut  off  under  the  curves 
by  the  ordinates  in  full  lines  are  measures  of  the  work  of  the 
most  efficient  drop-hammers,  while  those  cut  off  by  the  dotted 
ordinates  give  the  work  of  less  efficient  machines. 

173.  Copper,  Subjected  to  Transverse  Stress,  is  prob- 
ably always  to  be  considered  as  belonging  to  the  second  class 
of  materials  treated  of  in  Art.  161,  and  as  more  correctly  rep- 
resented by  the  equation  b  (p.  260)  of  Art.  166,  than  the 
usually  adopted  equations  preceding  them,  i.e. 

M1  =  R  '  f       ly<fydx,a.ndFt=27es,  P  r2  dry 

Jo   Jo  Jr0 

instead  of 


/?    f*    f 

=~\ 

"iJ0J 


dr, 


the  former  of  which,  for  rectangular  bearers  and  solid  shafts, 
would  become,  were  T=  C, 


instead  of 


STRENGTH  OF  NON-FERROUS  METALS. 


285 


The  values  of  T  and  C  are  not,  however,  the  same,  and 
the  differential  expression  must  be  integrated  for  the  two 
sides  of  the  bar  separately. 

Cast  copper,  tested  by  transverse  stress,  when  of  fair 
quality  should  give  figures  equal  to,  or  exceeding,  those 
obtained  in  the  record  which  follows : 


TABLE  XLII. 

TEST  OF  BAR  OF  CAST  COPPER. 

No.  55.— Material :  Copper,  cast  in  iron  mould.— Dimensions  :  Length  between  supports, 
7  =  22";  breadth,  3  — 0.985";  depth,  </=  0.970." 


LOAD. 

DEFLECTION. 

s 

MOD.  ELASTICITY. 

Q 

DEFLECTION. 

, 

MOD.  ELASTICITY. 

20 

c 

too 

5 
140 

i  So 

200 

5 
240 
280 
320 
360 
400 
5 
44° 

0.0033 
0.0075 
0.0176 
0.0224 

480 
500 

5 
540 
580 
Ruptured. 
580 
680 
720 
800 
840 
860 
Supports 
Breakinj 

Modulus 

0.4088 
0.4855 

o!8378 

15,792,947 
13,459*739 

0.3619 

0.0337 
0.0477 
0.0552 

0.0674 
0.0910 
o.  1176 

0.1553 
0.2057 

0.2883 

o  0095 

12,301,425 
11,174,068 
10,728,725 

0.8653 
1.46 

2-39 
2.85 

slid  out. 
fload,  P  = 

of  rupture 

10,540,763 
9,111,146 

Bar  bent. 
860  pounds. 

-30,^, 

0.1114 

The  modulus  of  rupture  for  good  cast  copper  should  thus 
exceed  30,000  pounds  per  square  inch  (2,109  kilogs.  per  sq. 
cm.),  but  may  be  expected  to  vary  between  20,000  and 
40,000  (1,406  and  2,812  kilogs.)  with  variations  in  the  sound- 
ness and  quality  of  the  metal. 

Rolled  Copper,  as  tested  by  the  Author,  when  of  good 
quality  and  sound,  may  give  values  of  the  modulus  of  rupt- 
ure as  high  as  ^  =  60,000  pounds  per  square  inch  (4,218 
kilogs.  per  sq.  cm.),  and  sometimes  exceeds  this  figure,  one 
test  under  the  eye  of  the  Author,  having  given  R  =  60,900 
£*  =  4,281. 


286  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 

174.  The  Modulus  of  Elasticity  of  Copper  is  almost  in- 
variably obtained  by  calculation  from  the  results  of  transverse 
tests,  using  the  expressions, 


~ 


for  the  general  case  and  for  rectangular  sections,  respec- 
tively,* when  the  weight  of  the  bar  may  be  neglected,  as  is 
the  case  with  metal  test-pieces,  usually.  By  reference  to  the 
records  of  tests  of  cast  copper  already  described  (Table 
XXXVI. ,  Art.  168),  it  will  be  seen  that  this  modulus  may 
vary,  with  even  the  variation  of  light  loads,  from  10  to  15 
million  pounds  per  square  inch  (703,000  to  1,054,500  kilogs. 
per  sq.  cm.),  and  the  same  differences  are  observable  as  a  con- 
sequence of  varying  quality.  The  higher  values  obtained  in 
any  one  test  are  the  most  probably  correct,  and  it  may  be 
assumed  that  the  modulus  of  elasticity  of  copper  approaches 
15,000,000  pounds  per  square  inch  (1,054,500  kilogs.  per  sq. 
cm.),  as  the  metal  is  obtained  in  a  state  approximating  purity 
and  soundness.  Usual  values  are  two-thirds  to  three-fourths 
these. 

Some  authorities  give  values  exceeding  the  maximum,  as 
above,  by  20  per  cent.,  but  such  figures  are  not  to  be  expected 
in  the  ordinary  work  of  the  engineer. 

Forged  and  wire-drawn  copper,  as  tested  by  Wertheim, 
gave  the  following  values  of  this  modulus : 

ZOLOGS.  PER  SQ.  CM. 

Copper,  hard-drawn 1,245,000 

- 1,254,000 

"          annealed     1,052,000 

"  "  1,254,000 

or  very  nearly  18,000,000  pounds  per  square  inch  for  hard- 
drawn,  and  20  per  cent,  less,  in  some  cases,  for  annealed 
wire. 

*  See  Part  II.,  p.  499,  §  268. 


STRENGTH  OF  NON-FERROUS  METALS.  2$J 

175.  Copper  Subjected  to  Torsion  is  found  to  exhibit 
the  same  variation  of  resistance  with  quality  and  physical 
structure  that  has  been  seen  in  other  methods  of  test.  The 
experiments  of  the  Author  give  values  of  j,  in  the  equations 
for  total  resistance,  Art.  166,  ranging  between  20,000  and 
40,000  pounds  per  square  inch  (1,406  and  2,812  kilogs.  per  sq. 
cm.),  the  lower  figure  for  cast  copper  of  ordinary  soundness, 
and  the  higher  for  good  forged  or  rolled  copper.  Thus  for 
the  two  cases,  it  may  be  assumed  that  copper  shafts  will 
break  under  load  when 


accordingly  as  they  are  made  of  cast  or  worked  copper,  when 
the  units  employed  are  inches  and  pounds,  or 


or  -  = 


when  the  units  are  metric. 

Copper  is  seldom  subjected,  however,  to  any  other  than 
tensile  stresses.  It  would  probably  be  more  correct  to 
use  the  expressions  in  Art.  166  for  tough  metals  than  the 
above,  making  the  true  value  of  st  =15,000  to  30,000 
pounds. 

176.  Results  of  all  Tests  of  Cast  Copper  made  for  the 
Committee  on  Alloys  of  the  U.  S.  Board  being  collected,  re- 
jecting all  tests  of  samples  known  to  be  defective,  the  follow- 
ing figures  were  obtained.  It  will  be  remembered  that  these 
experiments  were  made  with  ordinary  commercial  metals 
melted  and  cast  in  the  usual  way  and  purposely  without 
other  precaution  than  is  usually  taken  in  every-day  foundry 
work.  Much  higher  figures,  as  has  been  seen,  may  be  at- 
tained. 


288  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 

TABLE   XLIII. 

AVERAGE    OF    TESTS    OF    COPPER. 


TRANSVERSE    TESTS. 

TENSILE    TESTS. 

TORSIONAL    TESTS. 

CO 

'Q 

•g 

Tenacity  per 
square  inch 
of— 

0 
CO 

O 

8 

o 

1 

<u 

o 

CO 

si 

A 

£•0 

^ 

"o   • 

'^ 

13 

rt 

V--0 

w 

U 

rt  § 

MM 

5 

p_0 

§ 

^j 

o 

"C 

I 

a—1 

l.SP 

1 

it 

§ 

| 

es 

0  § 

88 

1  g> 

§ 

'hi 

g 

*"**i2 

o 

*P  1^ 

8 

o  ^ 

•^  ,^ 

*+H 

0 

be 

C 

a 

•o 
1 

18 

•8*° 

"5 

ji 

bJO 

•3 

c 

i 

1 

7 

8 

3 

8 

rt 

§ 

.H 

1 

£ 

PQ 

1 

w 

S 

£ 

1 

£ 

i 

s 

1 

H 

w 

& 

Brit.  Meas. 

765 

26,357 

0.232 

10,076,756 

0.0628 

23,118  26,817 

0.491 

118.06 

41.79 

o-354 

o  .  2630 

Metric  

348 

1,853 

0.232 

708,396 

0.0628 

1,625     15885 

0.491 

16.4 

5-8 

°-354 

0.263 

The  composition  of  these  bars  of  copper  was  found  to  be 


ANALYSES    OF    TURNINGS    FROM    FOUR    BARS    OF    COPPER. 


NO.   I. 

NO.  30. 

NO.  53. 

NO.  57. 

Metallic  silver  

O.OT? 

O.OI4 

0.015 

0.063 

Metallic  iron                  ,  . 

O  O2O 

O  OI4. 

O.O^1? 

O.OId. 

Metallic  zinc    ...»  

O   OI4 

O.O^7 

o  016 

None. 

Metallic  lead  

Trace. 

Trace. 

None. 

Trace. 

Metallic  bismuth             .      .        . 

None 

None 

None 

None. 

Metallic  arsenic  

None 

None. 

None 

None. 

None. 

None. 

None. 

None. 

Suboxide  of  copper               . 

12    O86 

q  e8o 

6  7^0 

i  .620 

Metallic  copper  

87    QOO 

06  ^o 

Q1  .  2OO 

08.  ^^o 

Insoluble  matter 

o  oo^ 

Carbon  ..     .. 

None 

100.055 

99-995 

99.996 

100.032 

177.  The  Strength  of  Tin,  as  obtained  in  the  market,  is 
variable  with  the  brand,  the  purity,  the  soundness,  and  den- 
sity of  the  metal,  with  the  temperature  and  the  velocity  of 
distortion  and  rupture,  and  with  other  variable  conditions,  as 


STRENGTH  OF  NON-FERROUS  METALS. 


289 


is  the  strength  of  copper,  but  in  less  degree  so  far  as  it  de- 
pends upon  the  skill  and  care  of  the  metallurgist.  It  is  less 
subject  to  injury  by  the  presence  of  deleterious  elements,  and 
is  less  liable  to  become  unsound  in  melting  and  casting. 

Mallet  obtained  a  tenacity  of  5,600  pounds  per  square 
inch  (3,936  kilogs.  per  sq.  cm.),  Rennie  about  5,000  pounds 
per  square  inch  (3,515  kilogs.  per  sq.  cm.),  and  the  Author 
has  obtained  figures  for  the  U.  S.  Board,  and  in  other  experi- 
ments, ranging  from  2,000  to  6,000  pounds  per  square  inch 
(1,406  to  4,218  kilogs.  per  sq.  cm.)  for  Banca  and  Australian 
tin  of  the  following  composition : 


COMPOSITION    OF    TIN    OF    COMMERCE. 


INGOT   BANCA 
TIN. 

INGOT 
QUEENSLAND 
TIN. 

Metallic  iron  

O.O^5 

O.O1^ 

None. 

None. 

Metallic  silver                     .        .        

Metallic  arsenic    

None 

Trace. 

None. 

None. 

Metallic  cobalt        .                                ... 

None. 

Metallic  bismuth  

None. 

None. 

Metallic  nickel 

None 

Metallic  lead               .               .                   

None 

o.  165 

Metallic  manganese  

0.006 

None. 

None. 

Metallic  tungsten       

None. 

Metallic  copper  

None. 

None. 

Metallic  tin                                                              . 

00.078 

QQ   704. 

Suboxide  of  copper      

Matter  insoluble  in  ap.ua  regia     ... 

Trace 

100.013 

IOO.OOO 

In  casting  tin  in  iron  moulds,  a  difficulty  was  met  with  in 
the  formation  of  surface  "  cold  -shuts,"  producing  an  irregu- 
lar section  in  bars  of  otherwise  sound  condition.     Tests  made 
as  above  give  data  as  follows : 
19 


2QO  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE   XLIV. 


TENSION   TESTS   OF  TIN   (Banco). 


Nos.  29  A,  and  29  B. 


W 

Pi 

VO 

26  • 

2 

K  £ 

Ii 

ll 

ii! 

Broke  %  inch  from  A  end. 

. 

p 

o  2 

%£< 

Diameter  of  fractured    section  0.490  inch 

1 

s 

H 

3*2 

(approximately).    The  section  was  very  much 
distorted,  and  an  exact  measurement  could 

not  be  obtained. 

Pounds. 
1,700 

Pounds. 

Inches. 
0.15 

.025 

Tenacity  per  square  inch  of  original  section, 
considering  1,400  pounds  as  the  breaking  load, 
2,800  pounds  (with  gradual  test)  (1,462  kilogs. 

o 

Set  0.15 

.025 

per  sq.  cm). 

Reduced  to  — 

1,250 

2,500 

0.19 

.0318 

In  2  m. 

2,500 

0.27 

•045 

1,400 

2,800 

0.32 

•°533 

In  10  m. 

2,800 

1.70 

•2833 

975 

1,950 

O.OI 

.0017 

Broke  2  inches  from  D  end. 

1,180 
1,290 

2,360 
2,580 

0.03 
0.09 

.0050 
.0150 

Fractured  section  very  irregular,  and  drawn 
out  almost  to  a  point.     Estimated  diameter  of 

i,  600 

2,000 

3,200 
4,000 

O.2O 

0.58 

.0332 
.0963 

final  section  0.300  inch. 
Tenacity  per  square  inch  of  original  section 

2,IOO                   4,2OO 

Piece  extending  rapid 

1.88 
ly  and  strain 

,    -3^3 
reduced  to— 

(with  rapid  test)  4,200  pounds  (2,953  kilogs. 
per  sq.  cm.). 

1,700 

3,400 

2.58 

.4269 

TABLE    XLV. 
Summary.. 


DIAMETER. 

il 

TENACITY    PER   SQUARE 

J,  u 

.2.5) 

l°lg 

NO 

ll 

ll 

*<D    C/3  *-* 

1.1 

ii 

w  3  S 

REMARKS. 

•"I 

rt  y 

I  oJ 

'££ 

rt  v 

jii 

o 

fo 

H 

0 

fe 

29A... 

29  B  ... 
Mean  .  . 

0.798 
0.798 

0.490 
0.300 
0.395 

0.2833 
0.4269 
o.355i 

2,800 

4,200 

Tenacity  of  frac- 
tured section 
doubtful. 

The  strength  per  square  inch  of  fractured  section  is  not 
given  for  comparison,  as  it  is  not  an  indication  of  either  the 
ultimate  or  the  useful  strength  of  the  metals,  except  they  have 
but  a  slight  ductility  and  show  no  increase  of  elongation  under 
continued  stress.  With  ductile  metals,  the  portion  of  the 


STRENGTH  OF  NON-FERROUS  METALS.  2$l 

test-piece  near  the  point  of  fracture  gradually  narrowed  down 
as  the  breaking  load  was  approached,  and  in  most  cases  this 
narrowing,  or  "  necking  down,"  was  very  rapid  just  before 
fracture.  In  such  cases  the  beam  of  the  scale  dropped  before 
fracture  took  place,  showing  decrease  of  resistance  and  de- 
crease of  stress.  The  final  rupture  was  caused  by  some  load 
less  than  the  maximum.  In  a  few  cases,  it  was  possible  to 
follow  the  decrease  of  resistance  by  balancing  the  scale-beam, 
nearly  to  the  instant  of  rupture,  but  the  actual  load  sustained 
by  the  piece  at  the  instant  of  rupture  could  never  be  deter- 
mined. The  so-called  "  tenacity  per  square  inch  of  fractured 
section,"  found  by  dividing  the  maximum  load  by  the  area 
of  section  measured  after  fracture,  is  no  measure  of  the  strength 
of  the  metal. 

This  peculiar  method  of  drawing  down  at  the  part  nearest 
the  section  ruptured  is 
well  shown  in  the  figure, 
and  may  be  taken  as  illus- 
trative of  this  action  in  all 
tough,  ductile  materials. 
The  influence  of  variation 
of  velocity  of  distortion 
will  be  exhibited  in  a  later 
chapter. 

Authorities  give  va- 
rious values  for  the  tenac- 
ity of  other  forms  of  tin, 
some  of  which  are  given 
above.  Trautwine  gives  FIG.  S.-FRACTURE  OF  TIN. 

for  block-tin  4,600  pounds,  and  for  wire  7,000  pounds  per 
square  inch  (2,854  and  4,921  kilogs.  per  sq.  cm.). 

Tests  by  Compression,  made  as  above,  gave  values  as  in  the 
succeeding  record : 


292  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

TABLE  XLVI. 

RESISTANCE   TO   COMPRESSION  :    CAST   TIN. 

No.  29  C.— Material :    Banca  tin,  cast  in  iron  mould. — Dimensions :    Length,  2"  ;  diametei 

0.625". 


COMP     PER 

LOAD. 

COMP. 

c. 

UNIT. 

1,250 
1,503 
1,750 
1,850 
1,900 
2,OOO 
2,000 

0.003 
O.OI2 
0.043 
0.097 
0.158 
0.265 
0.4/3 

4,074 

4,889 

5,704 

6,030 

6,193 
6.519 

6,5r9 

.0015 

.oo5o 
.0215 
.0485 
.0790 
•1325 
•2365 

At  1,850  pounds  (no  kilogs.  per  sq.  cm.), 
the  piece  was  observed  to  be  bulging  out 
on  all   sides,  but  still  remaining   vertical. 
At  the  end  of  the  test  the  piece  had  a  slight 
bend  in  one  direction,  and  was  increased  in 
diameter  to  0.85  and  0.89  inch  in  different 
parts  of  the  length. 

2,200 

0.612 

7iJ7i 

.3060 

2,300 

0.729 

7,497 

•3645 

2,300 

0.899 

7,497 

•4445 

With  tin,  as  with  copper,  and  all  ductile  metals,  the  re- 
sistance to  compression  per  unit  of  original  section  increases 
indefinitely  with  progressing  distortion,  and  probably  attains 
a  maximum,  as  reckoned  per  unit  of  momentary  sectional 
area,  when  the  intensity  of  stress  becomes  equal  to  the  resis- 
tance to  the  metal  to  continuous  flow. 

Elastic  limits  are  even  less  well  defined  with  tin  than  with 
copper,  and  the  resistance  rises  rapidly,  at  the  start,  as  distor- 
tion commences  and  progresses.  Resistance  to  compression 
is  stated  by  Trautwine  and  Haswell  as  above  15,000  pounds 
per  square  inch  (1,054  kilogs.  per  sq.  cm.). 

178.  Tin  under  Transverse  Test  behaves  much  like 
copper,  but  it  has  less  strength,  and  even  less  elasticity.  It  is 
the  best  representative  of  the  viscous  class  of  metals,  and,  as 
will  be  seen  in  the  chapter  on  conditions  modifying  strength 
of  the  non-ferrous  metals,  is  peculiarly  susceptible  to  varia- 
tion of  time  of  loading  and  rapidity  of  distortion.  Tests  of 
cast  tin  made  by  the  Author  for  the  government,  as  above, 
gave  data  of  which  the  following  is  fairly  illustrative: 


STRENGTH  OF  NON-FERROUS  METALS.  293 

TABLE  XLVII. 

CAST  TIN   IN  TRANSVERSE  TEST. 

No.  29. — Material :  Banca  tin,  cast  in  iron  mould. — Dimensions  :  Length  between  supports 
22"  ;  breadth,  0.993"  ;  depth,  1.002". 


Q 

9 

E 
•- 
a 

« 

MODULUS  OF  ELAS- 
TICITY. 

^4-T^r(/J+4) 

j 

Q 

h 

MODULUS  OF  ELAS- 
TICITY. 

'"fif*** 

Pounds. 
3 
5 

10 
20 
0 
24 
30 

35 

0 

40 

0 

45 

0 

50 

0 

60 

0 

70 

0 

80 

Inch. 
0.0008 
0.0032 
0.0^55 
0.0095 

0.012 
0.015 
O.OI7 

0.021 
0.029 

Inch. 

Pounds. 
8oh.  in  511 

In  10  m 
9° 

o 

100 

In  5  m. 
In  20  m. 

0 

no 
In  10  m. 

Breaking 
Modulus  < 

Inch. 
0.282 

i  199 

^360 
i  624 

2    124 

2    332 

S3* 
f  load,  no 
)f  rupture, 

Inch. 

o  265 

55 

2   065 

Bar  bent  am 
bottom  of 

sounds. 

R       3     /  ( 

. 

1  tray  reached 
supports. 

P+  3)  =  3,750. 
trie),  =  262.9 

6,734,838 

6,'ai8,983 
6,039,938 

0.0047 

0.0055 

5.583,107 

0.0095 

0.015. 

O.O2I. 
0.043. 

0.041 
0.062 
0.104 

0.218 

3,517,648 

2,750,622 

**  vbd* 
Rm  (me 

0.082. 

1,026,751 

Crack  observed  on  under  side  of  bar  extend 
ing  across  half  its  breadth. 


Tests  of  Queensland  and  Banca  tin,  compared,  stood  as 
follows : 


TRANSVERSE  TESTS  OF  TIN. 


1 

f 

Limit  of 
elasticity. 

.f 

MATERIAL. 

v  oi 

jj  2 

1 

S,! 

'5 

i 

j 

REMARKS. 

s 

a 

•5 

* 

to 

^e 

3  4 

•o 

Vs 

0] 

j3 

"3 

I 

(B 

1 

1 

1 

1 

| 

1 

1 

•*"" 

Ins. 

7«j. 

7«x. 

/>^r 

/«*. 

•9 

Queensland  tin.. 
Banca  tin  

22 
22 

1.038 
0-993 

1.023 

1.002 

150 
no 

4.559 
3.740 

t: 

4 
3 

.=67 
.273 

i'Js'J'i 

Bent. 
Bent. 

Mean  of  2  bars.. 

130 

4.150 

.270 

6,185,210 

294  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS 

Queensland  tin  proved  very  good,  showing  a  somewhat 
greater  strength  by  transverse  and  torsional  test  than  Banca 
tin,  but  a  less  strength  by  tension.  The  transverse  strength 
probably  appears  higher  than  it  should  be,  both  on  account  of 
different  methods  of  test,  the  Banca  tin  being  tested  by  dead 
loads  and  the  Queensland  tin  by  platform-scale,  and  on  account 
of  a  perceptible  flaw  in  the  centre  of  the  Banca  bar. 

In  the  test  of  No.  29,  as  above,  a  load  of  40  pounds  pro- 
duced a  set  of  0.0095  inch,  and  the  elastic  limit  appeared  to 
be  reached  at  about  30  pounds.  At  80  pounds  a  crack  was 
observed  on  one  of  the  edges  on  the  under  side  of  the  bar, 
which  gradually  opened  but  did  not  increase  in  length.  At 
1 10  pounds  the  bar  sank  gradually,  the  -deflection  increasing 
more  than  6  inches  in  ten  minutes.  The  bar  was  finally 
broken  by  repeated  bending,  and  showed  that  the  crack  above 
mentioned  was  produced  by  an  imperfection  in  the  casting, 
about  one-fourth  of  the  surface,  or  that  portion  in  which  the 
crack  was  observed,  showing  radiated  lines  of  cooling  and 
the  remainder  the  close  pasty  appearance  peculiar  to  tin  rupt- 
ured by  bending.  The  crack  weakened  the  bar,  and  the 
final  bending  was  resisted  by  but  little  more  than  three-fourths 
of  the  section. 

Major  Wade  found  the  tenacity  of  Banca  tin  used  in  mak- 
ing U.  S.  Army  ordnance  to  be  2,122  pounds  per  square  inch 
(148  kilogs.  per  sq.  cm.) ;  its  density  was  7,297. 

179.  The   Modulus  of  Elasticity  of  Tin  is  stated  by 
Tredgold  at  4,600,000  pounds  per  square  inch  (285,400  kilogs. 
per  sq.  cm.)  for  cast   metal,  by   Molesworth  at   same   figure 
nearly,  and  is  found  by  the   Author  to   vary  up    to  nearly 
7,000,000   pounds    (492,000   kilogs.,   nearly).      Some   of    the 
figures  obtained   are  given  in  the  records  of  transverse  tests 
of  cast  tin  already  referred  to. 

No  values  have  been  found  for  other  forms  of  this  metal. 
Tin  is,  however,  probably  less  affected  by  the  form  in  which 
it  enters  the  market  than  other  common  metals,  and  the 
moduli  here  given  may  be  accepted  for  general  use  as  sub- 
stantially accurate. 

180.  Tin  in  Torsion,   as   tested  by  the  Author,  gives 


STRENGTH  OF  NON-FERROUS  METALS. 


295 


figures  of  which  the  following,  from  the  Report  of  the  U.  S. 
Board,  may  be  taken-  as  fairly  representative  : 

TABLE   XLVIII. 

TORSIONAL   TESTS    OF    TIN. 
Averages  of  Results  calculated  from  Autographic  Strain-Diagram. 


ORDINATES 

TORSIONAL    MO- 

k 

« 

OF  DIAGRAM. 

MENT. 

s 

bp 

g 

i 

S 

1 

*i 

^ 

MATERIAL. 

i 

8 

B 

1 

°J5 

^ 

•a 

0 

g 

£ 

g 

3 

.« 

.2 

\ 

£ 

*o 

8 

3 

g 

I 

c 

«g 

& 

bo 

K 

"o 

X 

V 

M 

1 

9 

< 

3 

* 

O 
K 

58 

Queensland  tin  .. 
Banca  tin    

Sq.  ins. 
42.78 

21.20 

Degrees. 
691.0 
556.8 

Ins. 

0.22 

Ft.-lbs. 

Ft.-lbs. 
4.36 
5.78 

2.9029 
2.1975 

Ft.-lbs. 
208.48 
105.45 

3 
4 

Mean  (British)  ... 
Metric  .... 

O.l8 
0.46 

32.02 
20.6 

623.9 
623.9 

0.61 
1.6 

# 

5-07 
0.7 

2.5502 

156.97 

The  Queensland  tin  showed  an  extraordinary  ductility  in 
the  torsional  tests,  one  of  the  pieces  twisting  through  an  angle 
of  818  degrees,  or  more  than  2^  turns  before  breaking.  This 
represents  an  elongation  of  a  line  of  particles  parallel  to  the 
axis  on  the  surface  of  the  cylindrical  portion  of  the  test-piece 
from  one  inch  to  4.57  inches. 

The  average  of  all  tests  of  tin  is  given  in  the  following : 

AVERAGE  RESULTS   OF  TESTS   OF  TIN. 


TRANSVERSE    TESTS. 


TENSILE    TESTS. 


TORSIONAL    TESTS. 


I30 


—  c 

a'" 


4^50  I  .270 


•s 

CO 

I 

6,185,210 


—  part 
length. 


•355' 


Tenacity  per 

square  inch 

of— 


.476 


392   2.5502 


156.97 


296  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

181.  The  Strength  of  Zinc  has  been  determined  by 
but  few  investigators,  and,  like  that  of  all  other  useful  metals 
except  iron  and  steel,  is  a  subject  of  which  comparatively 
little  is  known  by  the  engineer. 

Cast  zinc  is  stated  to  have  a  tenacity  of  about  4,000  pounds 
per  square  inch  (281.2  kilogs.  per  sq.  cm.),  and  a  resistance  in 
compression  of  ten  times  that  amount.  Stoney  states  the 
tenacity  at  nearly  3,000  pounds  (211  kilogs.)  cast,  and  Traut- 
wine  gives  for  sheet-zinc  and  zinc  wire  16,000  and  22,000 
pounds  per  square  inch  (1,124.8  and  1,546.6  kilogs.  per  sq.  cm.), 
respectively.  The  modulus  of  elasticity  is  given  by  Wer- 
theim  and  by  Tredgold  at  from  12,000,000  to  nearly  14,000,000 
pounds  per  square  inch  (843,600  to  984,200  kilogs.  per  sq. 
cm.),  the  value  being  higher  for  cast  zinc.  The  Author  has 
obtained  much  smaller  figures. 

Pure  zinc,  like  pure  tin,  is  never  used  alone,  by  the  engi- 
neer, for  purposes  demanding  strength  and  toughness.  The 
values  of  the  several  moduli  are  given  as  of  interest,  how- 
ever, and  for  comparison. 

Samples  of  cast  zinc  tested  by  the  Author  show  variable 
tenacity,  the  figures  ranging  between  4,500  and  6,500  pounds 
per  square  inch  (2,847  to  4»253  kilogs.  per  sq.  cm.),  or  consid- 
erably above  those  given  by  earlier  investigators.  All  the 
zinc  thus  tested  by  the  Author  was  very  pure,  and  made  from 
New  Jersey  calamine.  The  effects  of  varying  time  and  rapid- 
ity of  strain  are  observable  in  zinc,  as  in  tin,  and  are  the  same 
in  kind ;  they  will  be  described  later. 

Zinc  is  much  less  ductile  than  tin. 

The  resistance  of  zinc  to  compression  varies  with  the  de- 
gree of  reduction,  and,  as  tested  by  the  Author,  was  about 
22,000  pounds  per  square  inch  (1,547  kilogs.  per  sq.  cm.)  when 
the  compression  amounted  to  one-tenth  the  original  height 
of  test-piece  in  pieces  three  diameters  long,  and  one-half 
greater  for  a  compression  of  one-third.  Zinc  is  weaker  under 
compression  than  any  copper-zinc  alloy. 

Zinc  has  no  defined  elastic  limit,  but  an  apparent  elastic 
limit  in  compression  was  recorded  at  5,000  pounds  per  square 
inch  (352  kilogs.  per  sq.  cm.). 


STRENGTH  OF  NON-FERROUS  METALS. 


297 


182.  Records  of  Test  of  Zinc  are  given  below,  as  reported 
to  the  U.  S.  Board. 


TABLE  XLIX. 

TENACITY  OF  CAST  ZINC. 

Length,  5";  diameter,  0.798". 


LOAD. 

TOTAL 
EXTENSION. 

SET. 

PER   CENT. 
ELONGATION. 

REMARKS. 

800 

O   OOI  I 

O  O2 

I  2OO 

0.0024. 

O   O2 

1,  600 

o,.  0014 

O  O7 

Section   o  706'' 

2,OOO 

0.0051 

O    IO 

Tenacity  6  300  pounds 

3,OOO 

0.0097 

O.  IQ 

per   square  inch   (4  420 

4,OOO 

0.0157 

•  O    11 

kilogs  per  so   cm  ) 

2OO 

o  0006 

5.OOO 

0.0206 

o  41 

6,OOO 

o  0240 

o  48 

6.3OO 

Broke. 

COMPRESSION  OF  CAST  ZINC. 
Length,  2"  ;    diameter,  0.625' 


COMPRES- 

COMPRES- 

LOAD. 

SION. 

LOAD. 

SION. 

Total. 

Per  sq.  in. 

Per  cent. 

Total. 

Per  sq.  in. 

Per  cent. 

1,000 

3,259 

0.15 

8,000 

26,076 

12.15 

2,000 

6,519 

0-55 

9,000 

29,335 

17-15 

3,000 

9,778 

1.85 

10,000 

32,595 

20.60 

4,000 

13,038 

3-40 

10,000 

a 

21.80 

5,000 

16,297 

5.10 

10,500* 

34,225 

24.40 

6,000 

19*557 

7.20 

Resistance  fell  to 

7,000 

22,816 

10.65 

10,000 

32,595 

33-35 

*  Continued  one  minute. 


298  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

CAST   ZINC   LOADED   TRANSVERSELY. 


LOAD. 

DEF. 

SET. 

E. 

REMARKS, 

2O 

O   OIOI 

40 
60 
80 
100 
120 
140 
a 

0.0171 
0.0246 

0.0324 
0.0424 
0.0506 
0.0616 

O  O 

6,698,725 
6,927,556 
6,984,644 
6,655,180 
6,680,965 
6,395,032 

Modulus  of  rupture, 
R  —  7,  540  pounds  per 
sq.  in.  (5,300  kilogs. 
per  sq.  cm.). 
Most  probable  value 
of    E    —     6,900  ooo 

1  60 
1  80 
2OO 

Broke 

0-0753 
0.0906 
0.1244 

5,973-588 

5,581,549 
1,797,132 

Em  —  428,130. 

TESTS   OF  CAST   ZINC   BY  TORSION. 

Length,  i"  ;  diameter,  0.625". 


NO. 

AREA   DIA- 
GRAM. 

ANGLE. 

MAX.  ORDI- 
NATE. 

MAX.    MO- 
MENT. 

EXTEX.     EXTER. 
FIBRE. 

21  A 

19.63 

123° 

2.15 

37-83 

o  .  2042 

21  C 

18.81 

I29 

2.07 

36.55 

0.2227 

21  D 

17.24 

151 

1-95 

34-42 

0.2955 

21  B 

18.13 

I63 

2.15 

37.83 

0.3380 

183.  Other  Metals  than  those  already  described  have 
been  made  the  subject  of  very  few  experiments  and  the  data 
obtainable  are  very  unsatisfactory.  The  alloys  of  the  three 
principal  non-ferrous  metals  are  made  the  subject  of  succeed- 
ing chapters. 

Lead  has  a  tenacity  which  is  reported  by  Haswell  as  : 


LBS.    PER   SQ.    IN. 

KILOGS.  PER  SQ.  CM. 

Lead,   cast 

I  8OO 

116 

"       milled     .         

233.4 

wire  

258O 

181.4 

In  compression  the  resistance  is  stated  to  be  7,700  pounds 


STRENGTH  OF  NON-FERROUS  METALS. 


299 


per  square  inch  (541  kilogs.  per  sq.  cm.)  and  the  modulus  of 
elasticity  is  given  as  720,000  Ibs.  (49,350  kilogs.).  Wertheim, 
however,  obtains  a  value  of  21,500,000  pounds  per  square 
inch  (175,750  kilogs.  per  sq.  cm.).  Trautwine  gives,  for 
tenacity : 


LBS.    PER    SQ.    IN. 

KILOGS.  PER.  SQ.  CM. 

Lead 

cast 

I  800  to  2,400 

116  5  to  168  7 

nine 

I  7OO  to  2  24O 

no  z  to  1^7  % 

« 

wire  

1,  6OO 

1  12    H 

« 

sheet 

I  Q2< 

re  c    c 

•"•ODO 

as  collated  from  various  older  experiments,  and  a  resistance 
to  compression,  agreeing  with  Haswell. 

The  strength  of  lead  pipe,  as  obtained  in  market,  has, 
when  tested,  been  found  variable.  The  best  results  noted  by 
the  Author  *  indicate  a  tenacity  of  the  metal  exceeding  one 
ton  per  square  inch  (2,240  Ibs.;  157.5  kilogs.  per  sq.  cm.). 
Comparing  the  results  of  a  number  of  experiments  to  obtain 
a  value  of/  in  Clark's  formula: 

/=  ThgR\ 


logR1 

in  which  T  is  the  tenacity,  /  the  pressure,  and  R  the  ratio  of 
external  and  internal  radii,  a  mean  value  of  T  was  found  to 
be  1.4  tons  per  square  inch  (220.5  kilogs.  per  square  cm.). 
The  minimum  value  was  three-fourths  as  great.  It  is  prob- 
able that  a  much  lower  pressure,  long  continued,  would  have 
burst  these  pipes. 

The  thickness  of  lead  pipe  is  frequently  determined  by  the 
rule  : 

/  =  0.0024  n  d  +  0.2, 

in  which  t  is  the  thickness  in  inches,  n  the  pressure  in  atmos- 
pheres and  d  the  internal  diameter  in  inches. 


Lond.  Engineer  ;  Nov.  16,  1883,  p.  378. 


300  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


Antimony  has  a  tenacity  of  about  1,000  pounds  per  square 
inch  (70  kilogs.  per  sq.  cm.),  and  bismuth  of  three  times  that 
amount.  Gold  is  a  moderately  strong  metal,  with  a  tenacity, 
cast,  of  20,000  pounds  per  square  inch,  and  of  30,000  in  wire 
(1,406  to  2,109  kilogs.  per  sq.  cm.).  Silver  is  reported  to  be 
about  equally  strong  (?)  in  the  two  forms,  having  a  tenacity 
of  40,000  pounds  per  square  inch  (2,812  kilogs.  per  sq.  cm.), 
according  to  Baudrimont.  Platinum  has  a  strength  of  from 
30,000  to  above  50,000  pounds  (2,109  to  3>5!5  kilogs.).  Nickel, 
tested  by  the  Author,  exhibited  tenacities  of  from  50,000  to 
54,000  pounds  per  square  inch  (3,515  to  3,543  kilogs.  per  sq. 
cm.),  elongating  about  10  per  cent.  Palladium,  tested  by 
Wertheim,  had  a  tenacity  equal  to  that  of  nickel.  It  is  ques- 
tionable whether  any  of  these  metals  have  a  true  elastic  limit. 

184.  Wertheim  on  Elasticity. — Wertheim  gives  the  fol- 
lowing as  the  densities,  atomic  weights,  and  products  of  the 
two,  and  also  the  tenacities  and  sound-conductivity  of  several 
metals : 


S.  G. 

AT.  WT. 

£ 
< 

X 

o* 

en 

RESISTANCE      TO 
RUPTURE    PER 
MILLIMETRE. 

Coefficient  of  elasticity 
(Tredgold). 

13 

e 

3 
o 

cfl 

"1 

3 
>,.u 

Tj 

'a, 

rt 
& 

Ji5 
gS 

QJ     4_>          • 

"5     ^^^ 

o  3  rt 
>P  > 

PQ"" 

£S 

If 

8|^ 

X  ^    ^ 

pp 

Lead  

H-352 
7.285 
19-258 
10.542 
6.861 
21.530 
8  850 
7.788 

12.94498 

7-35294 
12.43013 
6.75803 
4.03226 
12-33499 
3-95695 

3  •  39205 

0.8769 
0.9907 
1-5493 
J-5599 
1.7015 

1-7454 
2.2365 
2.2959 

O.O22 
0.063 
0.274 
0.341 
0.199 
0.499 
0-550 
1.  000 

i-45 
6.  20 

600 
3.200 

7-5 

Tin 

Gold  
Silver  

38.55 

9.600 
20.000 

9.0 

12.0 
17.0 

Zinc  
Platinum  
Copper  .  . 

Iron  

He  infers  a  general  variation  of  cohesion  with  change  of 
intramolecular  distances,  and  obtains  his  data  from  experi- 
ments upon  fifty-four  binary  alloys  and  nine  ternary  alloys, 
among  which  are  found  also  most  of  the  alloys  employed  in 


S TRENG TH  OF  NON-FERRO  US  ME TALS,  30 1 

the  arts,  such  as  brass,  pinchbeck,  gong-metal  annealed  and 
unannealed,  bronze,  packfong,  type-metal,  etc. 

These  experiments  gave  the  following  results : 

1st.  If  we  suppose  all  the  molecules  of  an  alloy  to  be  the 
same  distance  from  one  another,  we  find  that,  in  general,  the 
smaller  the  mean  distance,  the  greater  is  the  coefficient  of 
elasticity. 

2d.  The  coefficient  of  elasticity  of  the  alloys  agrees  suf- 
ficiently well  with  the  mean  of  the  coefficient  of  elasticity  of 
the  constituent  metals,  some  alloys  of  zinc  and  copper  being 
the  only  exceptions.  The  only  condensations  and  expan- 
sions which  occur  during  the  formation  of  the  alloy  do  not 
sensibly  affect  the  coefficient.  We  can  then  calculate  before- 
hand what  should  be  the  composition  of  an  alloy  in  order 
that  it  may  have  a  given  elasticity,  or  that  it  may  conduct 
sound  with  a  given  rapidity,  provided  that  this  elasticity  or 
this  velocity  fall  within  the  limits  of  the  values  of  these  same 
quantities  for  the  known  metals. 

3d.  Neither  the  tenacity,  nor  the  limit  of  elasticity,  nor 
the  maximum  elongation  of  an  alloy  can  be  determined  a 
priori  by  means  of  the  same  quantities  as  determined  for  the 
metals  which  compose  them. 

4th.  The  alloys  behave  like  the  simple  metals  as  to  longi- 
tudinal and  transverse  vibrations,  as  well  as  elongation. 

Wertheim,*  experimentally  determining  the  moduli  of 
elasticity  of  various  metals,  under  varying  conditions,  came 
to  the  following  conclusions : 

1st.  The  modulus  of  elasticity  is  not  constant  for  the  same 
metal ;  whatever  augments  the  density  increases  it,  and  re- 
ciprocally. 

2d.  The  longitudinal  and  transverse  vibrations  give  the 
same  modulus  of  elasticity. 

3d.  Vibration  gives  moduli  of  elasticity  much  greater  than 
those  obtained  by  elongation.  This  difference  is  due  to  the 
acceleration  of  movement  produced  by  liberated  heat. 

4th.  Consequently,  sound  in  solid  bodies  is  due  to  waves 
and  condensation,  and  we  may  be  able  by  means  of  the  for- 

*  Comptes  Rendus,  Vol.  15,  1842. 


3O2  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

mula  of  M.  Duhamel  to  find  the  relation  of  specific  heat  under 
constant  pressure  to  that  at  constant  volume.  This  ratio  is 
greater  for  annealed  than  for  non-annealed  metals. 

5th.  The  modulus  of  elasticity  diminishes  with  the  eleva- 
tion of  the  temperature  at  a  more  rapid  rate  than  that  which 
is  due  to  the  corresponding  dilation. 

6th.  Magnetization  does  not  sensibly  change  the  elasticity 
of  iron. 

/th.  The  elongation  of  rods  and  bars  by  the  application  of 
loads  affects  their  densities  very  slightly.  The  coefficient  of 
elasticity  should,  therefore,  vary  as  little  in  the  different  po- 
sitions of  equilibrium  ;  and  this  is,  in  fact,  what  takes  place,  in 
so  far  as  the  loads  do  not  become  great  enough  to  produce 
rupture.  The  law  of  Gerstner  is  therefore  confirmed  by  all 
the  metals  of  which  the  particles  take  a  position  of  equilibrium 
after  having  passed  their  limit  of  elasticity. 

8th.  The  permanent  alloys  are  not  found  intermittently, 
but  in  a  continuous  manner.  By  suitably  limiting  the  load 
and  its  duration  of  action,  such  permanent  elongation  as  may 
be  desired  can  be  produced. 

Qth.  No  true  limit  of  elasticity  exists ;  and  if  no  perma- 
nent elongation  is  observed  for  the  first  loads,  it  must  be  be- 
cause they  have  not  been  allowed  time  to  act,  and  because 
the  rod  submitted  to  the  experiment  is  too  short  relatively  to 
the  delicacy  of  the  measuring  instrument. 

The  values  of  maximum  elongation  and  of  cohesion  also 
depend  much  on  the  manner  of  operation.  They  become 
greater  the  more  slowly  the  loads  are  increased.  It  may  be 
seen  from  this  how  arbitrary  is  the  determination  of  least  and 
of  greatest  permanent  elongation,  and  that  we  cannot  found 
a  law  upon  their  values. 

loth.  The  resistance  to  rupture  is  considerably  dimin- 
ished by  annealing.  The  elevation  of  the  temperature,  even 
to  200°  C.,  does  not  greatly  diminish  the  cohesion  of  metals 
previously  annealed. 

Wertheim's  values  of  the  moduli  for  several  metals  are, 
in  round  numbers,  as  follow.* 

*  "Physique  Mecanique." 


STRENGTH  OF  NON-FERROUS  METALS. 
TABLE   L. 

MODULI   OF  ELASTICITY   OF   METALS. 


303 


LBS.    PER 
SQ.    IN. 

KILOGS.    PER 
SQ.    CM. 

Lead             

2,500  ooo 

176  ooo 

7,700,000 

492,000 

Gold                                     

II  500,000 

808  500 

Silver      .        

10,000  ooo 

70^  ooo 

17,000,000 

1,195,000 

Platinum              •           . 

24  ooo  ooo 

i  687  ooo 

Bischof  s  Method  of  Test  to  determine  the  purity  and 
economic  value  of  metals  consists  in  making  strips  of  a 
definite  and  standard  size  and  subjecting  them  to  repeated 
bending.  The  purer  the  metal,  as  a  rule,  the  greater  the 
number  of  changes  of  form  required  to  produce  fracture. 
Zinc,  for  example,  was  found  to  withstand  100,  54  or  19 
bendings  accordingly  as  it  was  pure  zinc,  best  commercial 
spelter  or  the  lowest  quality.  The  ill  effect  of  the  introduc- 
tion of  o.ooooi  tin,  or  of  0.0004  cadmium  is  perceivable  even 
more  certainly  than  by  analysis. 

Metals  which  do  not  alter  by  remelting,  as  tin  or  zinc,  are 
melted  in  crucibles,  with  continual  stirring  and  then  cast  in 
ingot  moulds,  12  cm.  long,  1.3  cm.  square  at  the  top  and  0.3 
cm.  square  at  the  bottom,  40  or  50  grammes  being  taken  for 
a  test,  or  60  grammes  for  lead.  The  bars  thus  made  are 
rolled  to  the  desired  thinness,  annealed  and  tested.  Metals, 
as  brass,  bronze  or  copper,  which  are  liable  to  change  in 
fusion,  are  rolled  from  the  commercial  form,  with  repeated 
annealing.  The  strips  tested  by  Bischof  were  13  cm.  (4  inches) 
long,  0.7  cm.  (2  inches)  wide  and  of  such  thickness  that  they 
weigh  as  follows:  Copper,  17;  brass,  16;  tin  and  zinc,  15; 
lead,  25  ;  iron  and  steel,  12  grammes.  They  were  tested  in  a 
"  metallometer,"  in  which  they  could  be  bent  conveniently  to 
any  angle.  Repeated  flexure  and  reflexure  through  an  angle 
of  67^  degrees  was  found  best  adapted  to  bring  out  the 
quality  of  the  metal.  Ten  strips  were  tested  simultaneously, 


304  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

and  fifty  tests  were  usually  made  of  each  metal,  occupying 
from  an  hour  to  an  hour  and  a  half.  The  following  are  some 
of  the  results : 


(l.)   ZINC. — NUMBER   OF   BENDINGS  OF   CHEMICALLY    PURE   ZINC — IOO. 


IOO  parts  chemically 

Hi' 

. 

pure  zinc  alloyed 

ta 

^  c  o 

with 

'a 

-6 

<u  -^  -p; 

e^  8 

. 

S 

.2 

"9 

rt 

&^  > 

s 

a 

U 

HJ 

uS 

M 

3 

5  .  o               parts  .... 

£ 

JS 

80 

0 

4.0                        

76 

C  ^ 

3.0 

S-d 

°T3 

93 

73 

V 

.  . 

2.0                                

C  jy 

C  jy 

77 

3  2 

.  . 

1.0                                

13  *2 

22 

95 

61 

(j  ^ 

0.5 

";3 

3 

54 

52 

0.25                      .... 

u 

u 

IOO 

61 

59 

95 

0.10                              

53 

29 

64 

64 

89 

0.05                   

57 

35 

.  . 

69 

62 

97 

0.025                 

57 

.  . 

83 

60 

0.0125                  .... 

45 

.  . 

82 

70 

0.00625              

63 

.  . 

85 

75 

.. 

0.003125              .... 

58 

92 

90 

0.0015625            .... 

69 

94 

88 

0.00078125         

90 

91 

93 

0.00039062         

85 

85 

0.00019531           .... 

84 

0.00004382         

89 

.  . 

0.00001095      '    .... 

93 

•  • 

•  • 

The  numbers  of  bendings  of  about  25  different  kinds  of  zinc  from  the  market 
were  found  to  lie  between  54  and  19. 

(2.)  TIN. — NUMBER   OF    BENDINGS   OF   BANCA  TIN  — TOO. 


IOO   PARTS    OF    BANCA   TIN   ALLOYED  WITH 

LEAD. 

ANTIMONY. 

2.5          "     

2O 

Ju 
Afi 

I.O          "     

ZV 

fi/l 

o.r       "    

J5 

°4 

0.05     "    

/• 

84 

The  numbers  of  bendings  of  4  kinds  of  Banca  tin,  obtained  through  different 
sources,  were  respectively  100,  101,  88,  and  78. 


STRENGTH  OF  NON-FERRO 


(3.)  LEAD. — NUMBER  OF   BENDINGS   OF  M  M  M   MECHERNICH   EXTRA — IOO. 


IOO  PARTS   OF  M   M  M   ALLOYED   WITH 

TIN. 

ANTIMONY. 

c.O    parts.  . 

e  I 

2.5         '    

CA 

\ 

i.o       "    

84 

71 

0.5        "    ,  

87 

74. 

O.I          "     

Ql 

IOO 

The  numbers  of  bendings  of  4  different  brands  of  lead  from  the  market  were 
found  between  100  and  89. 

185.   Aluminium,  according  to  Mr.  A.  E.  Hunt,*  gives 
the  following : 


FORM. 

RED.  OF 
AREA. 

POUNDS    PER    SQUARE    INCH. 

Elastic  Limit. 

Tenacity. 

Modulus 
Elasticity. 

Cast 

0.10 

.25 
.40 

.20 

5,000 

12,000 

16,000  to  30,000 

10,000 

15,000 
24,000 
30,000  to  65,000 
28,000 

11,000,000 
15,000,000 
15,000,000 
15,000,000 

Thin  sheet    

Bars 

In  compression  the  elastic  limit  is  found  at  about  3,500, 
the  ultimate  resistance  at  12,000.  The  modulus  of  resilience 
is  0.16  to  0.22.  In  shearing  it  ranges  from  12,000  to  16,000, 
about  equal  to  pure  copper.  Specific  gravity  varies  between 
2.55  and  2.65. 

Further,  are  given  the  following: 


MATERIAL. 

WEIGHT 
PER  CU.    FT. 

TENACITY, 
LBS.  PER  SQ.  IN. 

LENGTH  OF  BAR, 
SUSTAINING    ITSELF. 

444 

l6,OOO 

535  ft« 

K25 

3I,OOO 

Q.8Q3 

\Vrought  iron*     ..   

480 

5O,OOO 

15,000 

Al.  sheet  

165 

26,OOO 

23,000 

168 

55,OOO 

30,615 

cast                      

160 

15  ooo 

1^,^21 

forged  

165 

20,000 

17,700 

Its  conductivity  is  high,  it  is  non-magnetic,  sonorous,  and 
exceedingly  malleable.  It  has  many  valuable  alloys,  and  is 
much  used  in  iron  and  steel  castings  to  confer  soundness. 


*  Jour.  Franklin  lost.,  Feb.,  1891  ;  May,  1892. 


20 


CHAPTER   IX. 

STRENGTH    OF  BRONZES  AND   OTHER   COPPER-TIN  ALLOYS. 

186.  The  Bronzes — under  which  name  are  included  the 
principal  alloys  of  copper  and  tin,  and  a  few  special  composi- 
tions— vary,  in  strength,  elasticity,  ductility  and  hardness,  with 
variations  of  composition  to  such  an   extent  that  they  find 
application  in  an  immense  number  of  the  engineer's  construc- 
tions, their  character  and  chemical  constitution  being  adjusted 
to  his  needs.     The  most   common  of  these  alloys  is  "  gun- 
bronze,"  which  consists,  usually,  of  90  parts  copper,  10  of  tin, 
or  89  copper,  1 1  tin.     Such  bronze  has  a  strength  which  will 
depend  greatly  on  the  soundness  of  the  castings  and  purity 
of  the  constituents  of  the  alloy,  but  which  often  may  exceed 
50,000  pounds  per  square  inch  (3,515  kilogs.  per  sq.  cm.)  in 
tension. 

Bronze  used  for  journal-bearings  in  machinery  is  made 
harder  or  softer,  according  to  pressure  sustained,  the  com- 
position approaching  usually  that  of  gun-bronze,  and  ranging 
from  copper,  7;  tin,  i;  to  copper,  11,  tin,  i;  i.e.,  copper, 
87.5;  tin,  12.5,  to  copper,  91.67;  tin,  8.33.  A  little  zinc 
or  lead  added  slightly  softens  it.  Packing  rings  for  steam 
engines  are  made  of  still  softer  and  more  ductile  bronze — 
copper,  92,  to  copper,  96.  These  alloys  have  been  very  fully 
described  elsewhere,  and  this  chapter  is  devoted  entirely  to  the 
consideration  of  their  strength,  ductility,  elasticity  and  density. 

187.  Gun-bronze,  according  to  the  "  Ordnance  Manual," 
should   have  a  tenacity  of  42,000  pounds  per  square  inch 
(2,826  kilogs.  per  sq.  cm.),  and  a  specific  gravity  of  8.7. 

In  Major  Wade's  report  on  "  Experiments  on  Metals  for 
Cannon,"  1856,  are  given  records  of  a  number  of  tests  of  gun 
metal. 

Specimens  of  metal  from  83  " gun-heads"  (the  upper  part 


STRENGTH  OF  BRONZES.  3O/ 

of  the  casting  is  always  deficient  in  strength)  gave  an  average 
result  of  29,655  pounds  per  square  inch  (2,085  kilogs.  per  sq. 
cm.),  the  highest  figure  being  35,484  and  the  lowest  23,529 
pounds.  This  alloy  was  copper,  9;  tin,  I. 

Small  bars  made  of  gun  metal  gave  higher  figures.  One 
set  of  16  bars  gave  an  average  result  of  42,754  pounds  (3,006 
kilogs.  per  sq.  cm.),  and  another  similar  set  an  average  of 
41,284  pounds  (2,902  kilogs.  per  sq.  cm.),  the  lowest  figure  of 
the  32  specimens  being  23,854  pounds  and  the  highest  54,544 
pounds.  Five  of  the  specimens  gave  more  than  50,000  pounds 
(3,515  kilcgs.  per  sq.  cm.),  and  only  three  less  than  30,000 
pounds  (2,109  kilogs.  per  sq.  cm.). 

The  average  of  12  gun-heads  was  one-half  that  obtained 
from  the  small  sample  bars  cast  with  the  guns. 

A  sample  of  very  inferior  quality  fell  below  18,000  pounds 
(1,265  kilogs.  per  sq.  cm.). 

Major  Wade  found  the  quality  of  bronze  ordnance  enor- 
mously irregular  and  uncertain,  and  considered  it  very  im- 
portant that  a  more  reliable  method  of  manufacture  should 
be  found. 

The  tenacity  of  gun-bronze  thus  depends  greatly  upon 
the  method  of  manufacture,  of  casting,  and  of  cooling.  By 
careful  handling  it  has  been  given  a  tenacity,  in  ordnance, 
exceeding,  even,  60,000  pounds  per  square  inch  (4,218  kilogs. 
per  sq.  cm.),  and  the  Author  has  obtained  small  bars  still 
stronger.  Bronze  ordnance  of  large  size  has  been  made  here 
and  in  Europe  with  success ;  it  is,  however,  very  liable  to  be 
irregular  in  composition  and  physical  character,  and  the  un- 
certainty always  felt  in  regard  to  its  condition  is  an  element 
which  enters  into  the  question  of  its  use  for  any  purpose. 

Continual  use  of  ordnance  is  thought  to  lead  to  a  separation 
of  the  tin  from  the  copper,  and  to  final  destruction.  The 
gases  of  powder  sometimes  corrode  the  metal  badly. 

The  Modulus  of  Elasticity  of  gun-bronze  is  given  by  Tred- 
gold  at  10,000,000  pounds  per  square  inch  (703,000  kilogs.  per 
sq.  cm.),  and  this  figure  is  confirmed  by  the  experiments  of 
the  Author  as  given  later,  but  it  is  subject  to  great  variations 
with  the  condition  of  the  metal. 


308  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 


Gun-bronze  has  less  elastic  resilience,  and  therefore  less 
capacity  for  taking  up  shock  without  permanent  deformation, 
than  has  good  wrought  iron,  but  more  than  gun-iron  ;  it  wears 
more  seriously  than  iron,  and  the  finished  gun  is  considerably 
more  expensive,  nowithstanding  the  comparative  ease  with 
which  bronze  can  be  worked.  It  is,  therefore,  not  used  very 
extensively  for  ordnance,  and  is  less  generally  used  than  for- 
merly, when  steel  was  less  easily  obtained  for  this  purpose 
and  was  more  costly  than  at  present.  The  use  of  bronze 
ordnance  will  probably,  in  time,  cease  entirely. 

188.  Anderson's  Experiments  on  copper-tin  alloys,  ap- 
proximating to  the  composition  of  gun-bronze,  give  the  fol- 
lowing results,  the  tenacity  being  given  to  the  nearest  round 
numbers : 

TABLE  LI. 

TENACITY   OF   ORDNANCE   BRONZES. 


TENACITY,    T. 

LBS.  PER  SQ.  IN. 

KILOGS.  PER  SQ.  CM. 

Copper  92  '      tin    8           

29,OOO 
31,000 
33,OOO 
38,OOO 

2,039 

2,116 

2,130 
2,l65 

"           QI.7  '      "       8  ^     . 

"             OI  *           "        Q 

"            GO'          "     10 

189.  Bell-Metals. — Mallet,  testing  harder  alloys,  approach- 
ing bell-metal  in  character,  obtained  as  results  the  tenacities 
given  below: 

TABLE  LII. 


TENACITY   OF   BELL-METAL. 


TENACITY,    T. 


LBS.  PER  SQ.  IN. 

KILOGS.  PER  SQ.  CM. 

Copper,  84.29 

tin    15  71       

30  ooo 

2  cqo 

"         82  81 

"       17    IQ 

0/1   OOO 

"        81  10 

"     18  90 

40  ooo 

2  8l2 

78.9^ 

"      21  .03 

31  ooo 

2  Il6 

STRENGTH  OF  BRONZES. 


309 


190.    Gun-bronze  in   Compression   was   tested   by  the 
Author  with  the  following  results : 


TEST   OF   GUN-BRONZE. 


No.  1252. — Copper,  90;  tin,  10 ;  length,  2";  diameter,  0.769". 
Fluxed  with  mercury  sulphate  ;  sound. 


LOAD  J    LBS. 

COMPRESSION,   INCH. 

LOAD  J  LBS. 

COMPRESSION,  INCH. 

30,000 

0.6460 

36,000 

0.7914 

32,000 

0.6904 

38,000 

O.8II5 

34,000 

0.7311 

Resistance,  max.  123,860  Ibs.       per  sq.  inch,  original  area. 

8,707  kilogs.       "       cm.          "  " 

Compression,  in  per  cent.,  40.57. 

No.  1252-2  ;  as  above. 


LOAD  ;    LBS. 

COMPRESSION,    INCHES. 

LOAD  ;    LBS. 

COMPRESSION,    INCHES. 

lO.OOO 
15,000 

20  ooo 

O.OOO9 
0.2IIO 
O.35QQ 

25,000 
28,000 
23,  5OO 

0.5092 
0.8o62 

Max.  resistance,  92,894  Ibs.        per  sq.  inch. 

6, 530  kilogs.       "       cm. 
Compression,  40  per  cent. 

Gun-bronze  under  compression  behaves  as  exhibited  in  the 
accompanying  table.*  The  resistance  at  10  per  cent,  com- 
pression averages  about  40,000  pounds  per  square  inch  (2,812 
kilogs.  per  sq.  cm.) ;  at  50  per  cent,  about  140,000  pounds 
(9,842  kilogs.). 


*  Construction  of  Artillery,  Mallei. 


3IO    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


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STRENGTH  OF  BRONZES. 


These  experiments  were  made  by  Col.  Wilmot,  R.A.,  at 
Woolwich  Arsenal,  at  the  request  of  Mallet,  in  1856.  Nos. 
i,  2,  and  3  were  from  the  "  runner  "  cast  with  a  "  24-pounder  " 
howitzer.  No.  4  was  from  the  cascabel  of  a  similar  piece  of 
ordnance.  The  test  pieces  were  two  diameters  long,  0.5  inch 
by  I  inch  (1.27  by  2.54  cm.). 

191.  Hardness  of  Bronzes. — Riche  tested  the  hardness 
of  copper  and  bronze  with  an  apparatus  producing  an  in- 
dentation by  the  blow  of  a  drop  or  hammer  falling  upon  a 
steel  punch. 

The  hardness  of  bronze  increases  very  rapidly  with  the 
proportion  of  tin,  and  the  following  is  the  average  of  many 
experiments  with  the  apparatus  above  referred  to : 


Impacts  necessary 
in  order  to  ob- 
tain a  depres- 
sion of — 


4mm. 

I—. 

19 
23 
27 
38 
40 
Fid  no 
wilh  70  b 

7 
8  tog 
10 
14 
15 
:  succeed 
lows. 

Bronze  of  97 
Bronze  of  96 
Bronze  of  95 
Bronze  of  94 
Bronze  of  90 

parts  copper  

parts  copper     

parts  copper  

After  these  experiments,  medals  were  struck  at  the  mint 
in  Paris.  The  differences,  which  are  unimportant  for  medals 
less  than  35  millimeters,  become  more  noticeable  when  the 
dimensions  attain  to  50  millimeters  diameter.  There  are 
necessary  in  this  latter  case — 

With  pure  copper 7  compressions. 

With  bronze  of  97  parts  copper, 10  compressions. 

With  bronze  of  96.5  parts  copper 12  compressions. 

With  bronze  of  96  parts  copper 13  to  14  compressions. 

With  bronze  of  95  parts  copper 16  to  17  compressions. 

Alloy  of  95  copper,  4  tin,  I  zinc 14  compressions. 

Alloy  of  94  copper,  4  tin,  2  zinc 16  to  18  compressions. 


312    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


From  which  he  concludes  that  bronze  of  96  and  97  per 
cent,  copper  may  be  employed  to  great  advantage  and  with 
no  serious  inconvenience  in  the  manufacture  of  medals.  Its 
hardness  does  not  much  exceed  that  of  copper;  it  possesses 
sonority  and  casts  well,  rolls  evenly,  and  its  color  is  more 
artistic  than  that  of  copper.  The  action  of  the  press  and  of 
heat  modifies  its  density  but  little. 

The  hardness  and  brittleness  of  speculum  and  bell-metals 
are  such  as  to  forbid  the  use  of  this  method  of  testing  them. 

192.  "  Phosphor  Bronze  "  exhibits  much  greater  strength 
and  ductility  than  the  same  metal  cast  without  phosphorus. 
The  following  tables  exhibit  the  data  obtained  by  various 
experimenters  and  by  several  methods  of  test,  as  collated  by 
Dick.*  They  show  great  strength  and  remarkable  toughness. 

TABLE  LIV. 

TENACITY    OF    PHOSPHOR-BRONZE — {Kirkdldy). 


ULTIMATE 

PULLING    STRESS 

NUMBER    OF  TURNS 

PER  SQUARE  INCH. 

IN    PER    CT. 

IN  5  INCHES. 

Hard. 

Annealed. 

Annealed. 

Hard. 

Annealed. 

Copper 

63  122  Ibs 

37,002  Ibs. 

Mi 

86  7 

06 

Brass               

81  156 

CTCCJO 

36.1; 

14.   7 

1:7 

Charcoal  iron  

65,834 

46,160 

28 

48 

87 

Coke  iron. 

64  321 

6l  204 

17 

26 

A  A 

Steel     

1  20  076 

74,6^7 

IO.Q 

•j- 

70 

Phosphor-bronze  No.   I  . 

159.515 

58,853 

46.6 

13-3 

66 

do           do      No.  2. 

I5I,H9 

64,569 

42.8 

15-8 

60 

do           do      No.   3. 

139^41 

54,iit 

44.9 

17-3 

53 

do           do     No.  4. 

120,950 

53,38i 

42.4 

13 

124 

Elastic  stress  per 
square  inch. 

Ultimate    stress 
per  square  inch. 

Ultimate  permanent 
extension  in  per 
cent. 

Phosphor-bronze   No.  I  .  .  . 
do            do       No.  2.  .  . 
do            do       No.  3.  .  . 

Ibs. 
55,200 
40,500 
26,300 

Ibs. 
73,987 
63,653 
54,o6o 

per  cent. 
3-2 
94 
31-3 

*  Journal  Franklin   Institute,  1879. 

f  Of  the  8  pieces  of  Steel  tested,  3  stood  from  40  to  45  turns  and 

5      "        "      il  "    4     " 


STRENGTH  OF  BRONZES. 

TENACITY   OF   PHOSPHOR-BRONZE — (Uchatius). 


313 


Specimens. 

Absolute  resistance 
in  kilogs.  per  square 
centimetre. 

Elastic  resistance 
in  kilogs.  per  square 
centimetre. 

Stretch  in  per 
cent. 

Phosphor-bronze  No.    o. 
do            do      No.  oo. 
Krupp  Cast  Steel 

kilogs. 
3,600 
5,66o 

5,000 

kilogs. 
600 
3.800 

I    OOO 

per  ct. 
20.66 
i.  60 

II   OO 

TENACITY   OF   PHOSPHOR-BRONZE  ( Wofller}. 
Tests  by  Repeated  Application  of  Direct  Strain. 


PHOSPHOR-BRONZE. 


ORDINARY    GUN    METAL. 


Tensile  stress 

Number  of  efforts 

Tensile  stress 

Number  of  efforts 

per  square  in.        until  rupture. 

No. 

per  square  in. 

until  rupture. 

I 

10  Tons. 

408,350 

i 

10  Tons. 

j  Broke  before  total 
")  stress  was  applied. 

2 

12*       " 

147,850 

2 

10        " 

4,200 

3 

7i     *' 

3,100,000 

3 

7*      " 

6,300 

Tests  by  Repeated  Bending  in  the  same  Direction. 


PHOSPHOR-BRONZE. 


ORDINARY    GUN    METAL. 


No. 

Tensile  stress 
per  square  in. 

Number   of   bends 
until  rupture. 

No. 

Tensile  stress 
per  square  in. 

Number   of  bends 
until  rupture. 

i 

10  Tons. 

862,980 

i 

10  Tons. 

102,650 

2 

3 

7I  ;; 

4  Million  )  .,_,  e 

2 

3 

7?     " 

150,000 
837,760 

4 

6      " 

2       "       )      | 

A  bar  of  hammered  phosphor-bronze,  under  12  tons  per 
square  inch,  without  breaking,  stood  more  than  2y2  million 
turns,  whilst  according  to  Wohler's  experiments,  a  bar  of 
Krupp  cast  steel  under  12  tons,  broke  after  879,70x5  turns,  and 
another  bar  of  the  same  under  13  tons,  broke  after  1,007,550 
turns. 


MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

193.  The  Resistance  to  Abrasion  of  the  Phosphor- 
Bronzes  has  been  found  such  that  Dr.  Kunzel  has  adopted 
them,  with  the  addition  of  a  little  lead,  for  the  "  brasses  "  of 
railway  axles.  The  liquation  occurring  often  results  in  the 
production  of  two  alloys,  intermingled,  the  one  a  hard,  tough, 
strong  metal  which  acts  as  a  sponge,  retaining  the  softer 
alloy  very  uniformly  diffused  throughout  its  mass.  Kunzel 
considers  that  a  good  axle-bearing  should  not  be  homo- 
geneous, but  must  consist  of  a  tough  metal  skeleton,  the 
hardness  of  which  should  nearly  equal  that  of  the  axle,  and 
which  should  resist  any  pressure  or  shock  without  changing 
its  form  ;  the  pores  of  this  skeleton  should  be  filled  with  soft 
alloy.  The  nearer  the  hardness  of  the  skeleton  bearing 
approaches  the  hardness  of  the  axle,  the  better  this  skeleton 
will  resist  pressure  ;  and  the  softer  the  metal  which  fills  the 
pores,  the  more  excellent  is  the  bearing.  Such  a  bearing  is 
obtained  by  using  a  compound  of  two  or  more  metals  of  dif- 
ferent tempers  and  melting  points,  and  in  such  proportions 
that  necessarily  by  cooling  a  separation  of  the  metals  into 
two  parts  or  two  different  alloys  of  definite  composition 
results.  Bearings  of  phosphor-bronze  alloyed  with  lead  con- 
sist of  a  tough  and  homogeneous  skeleton,  the  hardness  of 
which  may  be  regulated  to  nearly  equal  the  hardness  of  the 
axle,  whilst  its  pores  are  filled  with  a  very  soft  alloy  ;  the 
wearing  part  of  such  bearings  may,  therefore,  be  considered 
as  consisting  of  a  great  number  of  small  bearings  of  soft 
metal,  each  of  which  is  surrounded  by  metal  of  nearly  the 
same  temper  as  the  axle  ;  Kunzel's  particles  of  soft  alloy 
may  be  easily  discerned.  When  this  alloy  is  heated  to  a 
dull  red,  the  soft  alloy  exudes,  whilst  a  hard  sponge-like 
mass  forming  the  skeleton  of  the  bearing  remains.  Herein 
consists  the  advantage  of  bearings  of  these  alloys,  the  axle 
running  partly  on  a  very  soft  metal,  whereby  heating  is 
obviated,  whilst  the  harder  part  of  the  bearing — its  skeleton 
— checks  the  wear  of  the  softer  metal.  The  following  table  * 
shows  the  result  of  a  series  of  experiments  on  such  bearings. 

*  Poly  tech.  Centralblatt,  Jan.,  1874. 


STRENGTH  OF  BRONZES. 


315 


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316  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

194.  Manganese  Bronze  is  another  valuable  alloy.  That 
used  in  the  construction  of  torpedo  boats  for  the  British 
navy  was  supplied  under  a  contract  calling  for  a  tenacity  of 
26  to  31  tons  per  square  inch  (4,094  to  4,882  kilogs  per  sq. 
cm.),  and  an  elongation  of  20  per  cent. 

This  sheet  bronze  was  from  T^th  to  Jth  inch  (0.16  to  0.32 
cm.)  thick  (No.  9  to  No.  18  B.  W.  G.),  and  sustained  29  to  30 
tons  (4,567  to  4,725  kilogs.),  stretching  25  to  35  per  cent.,  and 
bending  cold  to  a  radius  equal  to  their  thickness. 

Manganese  bronze,  tested  at  the  Royal  (British)  Gun  Fac- 
tory at  Woolwich,  England,  by  tension,  gave  the  following 
figures,  as  reported  to  the  Admiralty : 


TABLE  LVI. 

TENACITY   OF   MANGANESE   BRONZE. 
(Sheet  Metal ;  Rods  and  Bolts.) 


NOS. 

LOADS 

ELONGA- 
TION. 

Yielding. 

Breaking. 

Tons  per    Kgs.  per 

Tons  per 

Kgs.  per 

Per 

sq.  in. 

sq.  cm. 

sq.  in. 

sq.  cm. 

cent. 

4,766 

14.0 

2,204 

24-3 

3,817 

8.7 

Cast  in  metal  mould. 

4,767 

12.6 

1,984 

29.0 

4,567 

31-8 

Ditto             and  forged. 

4,768 

14.0 

2,204 

22.  1 

3.480 

5-5 

Ditto. 

4,769 

I"  .2 

2,079 

28.8 

4,535 

35-3 

Ditto             and  forged. 

^   1    4,77° 

16.8 

2,645 

23.6 

3-8 

Cast  in  metal  mould,  slight  flaw 

*o 

in  specimen. 

c 

4,771 

12.0 

1,890 

30-3 

4,772 

25.7 

Cast  in  metal  mould  and  forged. 

|- 

rt 

ROLLED    RODS. 

1 

6,536 
6,545 

II.  O 

16.6 

1,732 

2,615 

29.0 

4,567 
4,835 

44-6 
20.7 

Mild,  for  ships'  bolts  and  rivets. 
High,    for     Engineers'     bolts, 

6,546 

14.6 

2,299 

30.0 

4,725 

26.2 

pump  rods,  etc. 
Medium. 

6,547 

34-4 

39-6 

6;237 

ii.  6 

Cold  rolled. 

AREA  OF   SPECIMENS,  0. 133    INCH.      LENGTH  OF   BREAKING   PART,  2   INCHES. 


{7,364 

13.8 

2,I73 

28.57 

4  5°4 

28.7 

Pulled  in  direction  of  fibre. 

7,365 

14.06 

2,205 

28.46 

4488 

23.2 

Across  fibre. 

7,369 

14.06 

2,205 

3°-!3 

4  740 

47-8 

With  fibre. 

7,372 

14.8 

30.78 

4  850 

Across  fibre. 

7,374 

16.7 

2,630 

30.1 

4740 

28.8 

With  fibre. 

STRENGTH  OF  BRONZES. 


317 


Manganese  bronze,  tested  by  transverse  stress,  has  been 
found  to  possess  great  strength,  flexibility,  and  toughness. 
The  following  are  figures  given  the  Author  by  the  inventor, 
as  obtained  by  tests  made  in  presence  of  the  Inspector  to  the 
British  Admiralty,  January,  1881  : 


TABLE  LVII. 

TRANSVERSE  STRENGTH   OF  MANGANESE  BRONZE. 
[Length,  i  foot  (0.3  m.) ;  Section,  i  in.  (2.54  cm.)  square.] 


LOAD   AT   MIDDLE    OF  BAR. 

Elastic  Limit. 

At  Rupture. 

Lbs. 

2,688 
1,232 

Kgs. 

122 

56 

Lbs. 

6,048 
2,912 

Kgs. 

'  275 
132 

Gun  (Copper-tin)  Bronze 

195.  Manganese  Bronze  tested  by  Impact,  resisted  the 
blow  as  shown  in  the  following  table,  furnished  the  Author 
by  the  inventor ; 


3l8  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


i— i      trt     .3 


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H      N      o      «      ro 


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moo       N 


STRENGTH  OF  BRONZES. 


319 


The  wrought  iron  was  of  three  grades ;  the  gun-metal 
was  partly  (Nos.  I,  2,  3),  of  usual  good  quality,  and  partly 
(Nos.  4,  5)  specially  made  for  the  test  of  copper,  16,  tin,  2,  and 
copper,  16,  tin,  2%.  The  manganese  was  of  several  grades. 
No.  6  was  annealed. 

196.  Copper  and  Iron,  in  the  proportions  varying  from 
copper,  93. 5,  iron,  6.5,  to  copper,  96,  iron,  4,  was  tested  by  M. 
Riche,*  and  the  alloy  compared  with  copper,  as  below, 


TABLE  LIX. 

TENACITY   OF   FERROUS   COPPER. 
Elongations  in  millimetres  corresponding  to  loads  in  kilogrammes. 


NAME  OF  METALS. 

*§ 
fc£ 

i\ 

li. 

94 
95 
in 
98 
92 
92 
97 
97 
81  5 

800 

0 

0.5 
1-25 
25 
0.25 
0.25 

1,000  1,100 

.     is 
0.5    0.5 

3.0   4.5 
5.0    U) 
0.25  0.25 
0.25   0.25 

1,200 

5 
0.5 

5.5 

1,300 

(t) 

o-S 
6.0 

1,400 

1,500 

i,  600 

1,700 

Copper  of  commerce,  melted  .  . 
Copper  of  commerce,  rolled.  . 
Pure  copper,  melted  
Pure  copper,  melted 

0-5 

0-5 

0.5 

o-5 

Copper  and  iron,  melted  
Copper  and  iron,  melted  
Copper  and  iron,  melted  ...   . 
Copper  and  iron,  melted  
Pure  copper  rolled 

2 
2 

4-5 
4-5 

0.25 
0.25 

o  75 
0.50 

'•5 

2.O 

2-5 

3-o 

(§) 
3-5 

3-5 

4-5 
4-5 

ft 

90 

Copper  and  iron,  rolled  
Copper  and  iron,  rolled  

NAME  OF   METALS. 

*g 

-- 

1,800 

1,000 

2,000 

2,100 

2,200 

2,300 

2,400 

2,500 

2,600 

2,700 

2,800 

Copper      of      commerce, 

Copper     of      commerce, 
rolled  

0.5 

0-5 

1-5 

2-5 

4-5 

5.5 

.... 

.... 

Copper  and  iron,  melted. 
Copper  and  iron,  melted. 

2 

2 

4-5 

5-5 

7.0 

2.5 

8.5 

(I) 

10.  0 

"•5 

15.0 

Copper  and  iron,  melted. 
Pure  copper,  rolled  
Pure  copper,  rolled  

4-5 

0.25 
0-5 

0.25 

12.0 

16.00 

x.o 

1.  20 

'•75 

8-5 

4.0 

0.25 
i.S 

2.0 
3-0 

4.0 
4-5 

8.75 
8.0 

*  (Ann.  de  C/iim.  et  de  Phys.,  4  strie,  t.  xxx.,  Nov.,  1873,  26.) 

f  The  test  was  arrested  because  a  blowhole  was  formed  in  the  sample. 

\  The  broken  section  presents  blowholes. 

§  At  i, 600  kilogrammes  one  lug  of  the  piece  was  broken, 

I   The  sample  broke  without  the  two  pieces  being  entirely  separated 


32O  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


NAME  OF  METALS. 

Per 

ct. 

2,900 

3,000 

3,100 

3,200 

3,3°° 

3,4oo 

3,5oo 

3,6co 

Breaking  load. 

&. 

*s 

I* 

C/3 

>, 

1 

Q 

Copper    of    commerce, 
melted 

Kilog. 

Kilog. 

Copper    of     commerce, 
rolled 

2,300 

1,300 
1,000 

11.711 

8.039 

Pure  copper  melted 

Copper  and  iron,  melted 
Copper  and  iron,  melted 
Copper  and  iron,  melted 
Copper  and  iron,  melted 
Pure  copper  rolled 

2 
2 

4-5 
4-5 

26.086 

2,800 
2,300 
2,300 
3,500 
3,600 

28.  £65 
28.220 
25.842 
39-772 
40.000 

8.879 
8.904 

8.891 

Pure  copper,  rolled  
Copper  and  iron,  rolled. 
Copper  and  iron,  rolled  . 

4-5 
4-5 

0.25 

o.S 

o.S 

I.O 

0.25 

2-5 
o-75 

2-5 

»«5 

4-75 
3-5 

9.0 

OBSERVATION.— The  melted  copper  (Nos.  i,  3,  4)  contains  blowholes  which  destroy  its 
tenacity.  It  elongates  under  light  loads,  and  breaks,  also,  under  a  small  load.  The  copper 
acquires  a  certain  tenacity  by  rolling.  While  the  resistance  of  melted  copper  is  from  10  to  12 
kilograms  per  square  millimetre,  that  of  the  same  copper  attains,  by  rolling,  25  to  28  kilo- 
grams. The  ductility  is  less,  and  the  elongation  becomes  no  longer  evident  under  loads  of 
i, 800  kilograms. 

finding  a  decided  gain  of  strength  and  hardness  with  no  loss 
of  malleability.  The  same  metals  subjected  to  the  action  of 
a  punch,  were  indented  in  the  proportions,  cast  copper,  2.5  ; 
rolled  copper,  1.5  ;  with  0.03  iron,  cast,  i.i  ;  rolled,  0.9.  , 

197.  The  Copper-Tin  Alloys,  which,  as  has  been  stated, 
furnish  a  very  large  number  of  the  best  bronzes  and  engi- 
neers' compositions,  and  which  are  extensively  used  in  every 
department  of  construction  and  the  arts,  had  never  been  sys- 
tematically studied  until  the  investigation  was  made  by  the 
U.  S.  Government  Board  upon  a  plan  prepared,  proposed, 
and  carried  out  at  the  request  of  that  Board,  by  the  Author. 
Earlier  investigations  had  been  confined  to  a  few  familiar 
compositions,  and  it  was  only  when  appropriations  made  by 
the  Congress  of  the  United  States  could  be  applied  to  such 
a  research  that  it  became  possible  to  determine  the  method 
of  variation  of  strength,  elasticity,  and  ductility,  and  of  spe- 
cific gravity,  and  other  properties,  with  variation  of  compo- 
sition throughout  all  the  possible  proportions  of  copper  and 
tin  alloys.  In  the  research  to  be  described  the  principal  as- 
sistant employed  by  the  Author  was  Mr.  William  Kent. 


S TRENG  TH  OF  BRONZES.  3 2 1 

This  investigation  of  the  strength,  ductility,  and  other 
properties  of  all  alloys  of  copper  with  tin  was  made  in  the 
Mechanical  Laboratory  of  the  Stevens  Institute  of  Technol- 
ogy, in  the  years  1875-1878,  for  the  Committee  on  Alloys  of 
the  United  States  Board  appointed  to  test  the  useful  metals 
of  the  United  States,  and  the  facts  and  data  here  to  be  given 
are  mainly  condensed  from  the  reports  made  to  that  board  * 
and  the  notes  taken  by  the  Author.  This  work  was  supple- 
mented by  private  investigations,  of  which  an  account  will 
also  be  given. 

The  intention  in  the  work  here  to  be  described  was,  not 
to  determine  the  character  of  chemically  pure  metals,  melted, 
cast,  and  cooled  with  special  precaution,  but  to  ascertain  the 
practical  value  of  commercial  metals,  as  found  in  the  markets 
of  the  United  States,  melted  in  the  way  that  such  alloys  are 
prepared  in  every  foundry  for  business  purposes,  and  cast 
and  otherwise  treated  in  every  respect  as  the  brass-founder 
usually  handles  his  work;  and  to  determine  what  is  the  prac- 
tical value,  to  the  brass-founder  and  to  the  constructor,  of 
commercial  materials,  treated  in  the  ordinary  manner  and 
without  any  special  precaution  or  any  peculiar  treatment. 

The  result  was  the  complete  exploration  of  a  broad  and 
most  important  field  of  which  almost  nothing  was  previously 
known. 

The  whole  field  having  been  explored  the  useful  alloys 
are  proven  to  occupy  but  a  limited  portion  of  its  great  ex- 
tent, and  it  has  been  now  shown  that  a  comparatively  narrow 
band,  extending  from  ordnance-bronze,  on  the  one  side  of  this 
triangular  territory,  to  Muntz  metal,  on  the  other,  contains 
all  of  the  best  of  the  generally  useful  alloys.  This  small  por- 
tion of  valuable  territory  having  been  pointed  out  and  de- 
fined, its  more  minute  study  was  left  for  future  investigators. 

The  reader  should  make  a  careful  study  of  the  graphical 

*  Executive  Document  98,  45th  Congress  ;  Ex.  Doc.  23,  40th  Congress,  2nd 
Sessions  ;  1878-1881.  In  the  text  of  the  report  will  be  found  a  statement  of  the 
more  important  facts  determined,  and  the  tables  appended  contain  all  the  results 
of  observation.  The  whole  forms  a  collection  of  facts  that  will  probably  repay  a 
vastly  more  complete  analysis  and  more  careful  study  than  it  has  yet  been  pos- 
sible to  give  them. 
21 


322    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


representation  of  the  results  of  the  research  on  the  alloys,  as 
presenting  most  completely  and  satisfactorily  the  character- 
istics of  the  metals  used. 

The  researches  consisted  of  an  investigation  of  the  proper- 
ties of  the  alloys  of  copper  and  tin,  cast  in  the  form  of  bars 
about  28  inches  (71.1  cm.)  long  and  I  inch  (2.54  cm.)  square 
in  section,  prepared  from  the  commercial  metals,  only  ordi- 
nary precautions  being  taken  to  secure  good  castings.  It  was 
desired  to  learn  also  the  laws  which  connected  these  proper- 
ties with  the  proportions  of  the  component  metals,  and 
whether  alloys  mixed  in  simple  proportions  of  the  chemical 
equivalents  of  the  component  metals  possessed  advantages 
over  other  mixtures. 

198.  The  Metals  used  were  the  best  Lake  Superior  cop- 
per and  Banca  tin  :  they  had  the  following  compositions  : 


INGOT   LAKE    SU- 
PERIOR COPPER. 

INGOT  BANCA  TIN. 

Metallic  iron 

o  013 

Metallic  zinc.              .  .                              . 

None 

U-UJD 

Metallic  silver  

o  014 

None. 

Metallic  antimony                           .  . 

None 

Metallic  cobalt  

Metallic  bismuth 

Metallic  nickel. 

Metallic  lead   

Trace 

Metallic  manganese 

Metallic  molybdenum  .                    . 

Metallic  tungsten  

Metallic  copper  

OQ    4.2O 

None 

Metallic  tin      ... 

QO    O78 

Suboxide  of  copper  

O    ^^7 

yv-y/° 

Carbon  

0.04.  1 

Matter  insoluble  in  aoua  regia 

Trace 

100.025 

100.013 

199.  Alloys  Tested. — The  following  table  gives  the  com- 
position of  the  alloys  made,  according  to  their  atomic  pro- 
portions and  percentages  of  original  mixture,  and  according 
to  chemical  analysis  after  test. 


STRENGTH  OF  BRONZES. 


323 


TABLE   LX. 

ALLOYS   OF  COPPER  AND  TIN. — FIRST   SERIES. 
Composition  by  Original  Mixture  and  Analysis. 


NUMBER. 

ATOMIC  PROPOR- 
TION. 

PERCENTAGE    BY 
ORIGINAL  MIX- 
TURE. 

MEAN    PERCENT- 
AGE BY  ANALY- 
SIS. 

MEAN  SPECIFIC 
GRAVITY. 

Cu. 

Sn. 

Cu. 

Sn. 

Cu. 

Sn. 

j  

I 
96 
48 
24 

o 

i 

i 
i 

i 
i 
i 

i 

5 

i 

7 

2 

3 
5 

i 

4 

5 

2 

3 
4 

5 

12 

48 
96 

I 

100 
98.1 
96.27 
92.80 
90.00 

86.57 
80.00 
76.32 
70.00 
68.25 
65.00 
61.71 
56.32 
51.80 
47-95 
44-63 
41.74 
39-20 

34-95 
28.72 
24.38 

21.  IS 

15.19 
II.S4 
9.70 
4-29 
I.  II 

0-557 
O 

0 

i-9 
3-73 
7.20 

10.00 

13.43 

20.00 

23.68 
30.00 
31-75 

35-co 
38.29 
43-68 
48.20 
52.05 
55-57 
58.26 
60.80 
65-05 
71.28 
75.62 
78.82 
84.81 
88.16 
90.30 

95-71 
98.89 

99-443 

100 

8.487 
8.564 
8.649 
8.694 
8.669 
8.681 
8.740 
8.565 
8.932 
8.938 
8.947 
8.970 

8.682 
8.560 
8.442 
8.312 
8.302 
8.182 
8.013 
7.948 
7.835 
7.770 
7.657 
7-552 
7.487 
7.36o 
7.305 
7.299 
7.293 

2                                ... 

97.89 
96.06 
92.11 
90.27 

87.15 
80.95 

76.64 
69.84 
68.58 
65-34 
62.31 
56.70 
51.62 
47.61 
44-52 
42.38 

3^-37 

34-22 

25-85 
23-35 
20.25 
15.08 
11.49 
8-57 
3-72 
0.74 
0.32 

1.90 
3.76 
7.80 
9-58 
12.73 
18.84 
23-24 
29.89 
31.26 
34-47 
37-35 
43-17 
48.09 

52-14 
55-28 
57-30 
61.32 
65.80 
73-80 
76.29 
79  63 
84.62 
88.47 
91-39 
96.31 
99.02 
99.46 

a 

c 

6     ..             ... 

12 

7 

8     

6 

IO 

4 

II      

12  

3 

12 
2 
12 

3 

6 

I 
3 
3 

o 

11 

14. 

16 

17    . 

18  

IQ 

21 

24 

25  

26                           .       . 

27 

28 

2Q 

324  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

SECOND    SERIES. 


NUMBER. 

COMPOSITION     OF 
ORIGINAL     MIXTURE. 

MEAN    COMPOSITION 
BY  ANALYSIS. 

MEAN 
SPECIFIC 
GRAVITY. 

Copper. 

Tin. 

Copper. 

Tin. 

OJ 

97.5 
92.5 

87.5 
82.5 

77-5 
72-5 
67-5 
62.5 

57-5 
52-5 
47-5 
42.5 
37-5 
32.5 
27-5 

22.  5 
17-5 

12.5 

7-5 
2.5 

2.5 
7.5 
12-5 

17.5 

22.5 

27-5 

32-5 

37-5 
42.5 
47-5 
52.5 
57-5 
62.5 

67-5 
72.5 
77-5 
82.5 
87-5 
92  5 
97-5 

99.09 
94.10 
88.40 
82.72 
77-56 
72.89 

67-87 
62.42 
57-87 
53-46 
47-27 
43-99 
37.10 
30.76 
26.62 

22.  IO 
16.70 

u.68 
6.05 

2.  II 

0.87 
5-43 
n-59 
17-33 
22.25 
26.85 
32-09 
37.48 
42.05 
46  54 
52-72 

55-91 
62.90 
69.19 

73-18 
77-58 
83-23 

88.25 

93-77 
97-68 

•32 

8.684 
8.647 
8.792 
8.917 
8-925 
8.907 
8-956 
8.781 
8.643 
8.445 
8-437 

8.101 
7-931 
7-9T5 
7-774 
7.690 
7.542 
7.419 
7-343 

VA 

•je 

36*    . 

q7 

<*8.  . 

3Q    . 

AQ 

4.1 

42  

4.  "3 

44. 

4.^  .  . 

46  

4.7 

48.. 

4Q 

CO 

200.  Temperatures  of  Casting. — The  following  are  the 
temperatures  at  which  some  of  these  alloys  were  poured 
into  the  ingot-moulds.  They  vary  irregularly,  but  show  a 
general  decrease  from  a  maximum  for  alloys  richest  in  cop- 
per to  alloys  containing  most  tin.  These  temperatures  are 
evidently  not  those  of  fusion  of  the  several  alloys,  but  are 
somewhat  above  in  all  cases,  and  are  several  hundred  degrees 
above  the  melting  points,  usually.  The  determination  was 
made  by  pouring  a  small  portion  of  molten  alloy  into  a 
known  weight  of  water,  noting  the  rise  in  temperature  of  the 
latter,  and,  from  it,  calculating  the  loss  of  temperature  of 
the  alloy. 

*  Second  casting ;  first  broke  in  emery  planer. 


STRENGTH  OF  BRONZES. 
TABLE   LXI. 

ESTIMATED   TEMPERATURES   OF   CASTING. 


325 


COMPOSITION     BY 

K 

a 

j 
< 

TEMPERATURES      OF 

y 

E 

CALCULATED    RELA- 

ORIGINAL   MIX- 

5 

WATER,       CENTI- 

8 

TIVE      TEMPERA- 

TURES. 

s 

GRADE   SCALE. 

s  . 

(f,  H 

TURE. 

NUMBER. 

b. 

< 

tm 

O 

0 
O 

u 

, 

8  = 

i 

I 

X 

X 

o 

3 

"c3 

Gf 

H 

-Ld 

li 

& 

u 

g 

I 

1 

1 

i 

1 

1 

1! 

Gram. 

0*»r. 

31..    -     - 

97-5 

2.5 

907 

74 

8-3 

22.8 

14-5 

0.004177 

1909.9 

3469.8 

33- 

92.5 
87.5 

7-5 
12.5 

907 
907 

101 

12.8 

16.7 

%'•* 

18.9 
26.1 

0.092231 
0.090285 

1871.9 

1802.6 

3401.4 
3276.6 

34-- 

82.5 

17.5 

907 

362 

9-4 

60.0      50.6 

0.088:39 

I495-I 

2723.0 

11" 

77-5 

22.5 

907 

225 

15-0 

47  3 

32-3 

0.086393 

1554-5 

2829.2 

36.. 

72.5 

27-5 

907 

157 

"•7  :  33-3 

21.6 

0.084447 

1511.8 

2751.8 

37-- 

67-5 

32-5 

907 

97 

u.i      26.1 

i5-o 

0.082501 

1726.2 

3148.8 

38.. 

62.5 

37  5 

9°7 

177 

10.6         31.7        21.  I 

0.080555 

'373-9 

2503.4 

39- 

57-5 

42-5 

907 

129 

17.2     32.8     15.6 

0.078609 

1428.0 

2602.4 

40.. 

52.5 

47-5 

907 

214 

8-3 

35.0     26.7 

0.076663 

15^1.1 

2751.8 

41.. 

47-5 

52-5 

907 

216 

12.2 

5°-5 

38.3 

0.0747^7 

2205.0 

4001.0 

42.. 
43- 

42-5 
37-5 

57-5 
62.5 

907 
907 

328 
293 

9-5 
13-9 

47-2 
38.9 

37-8 
25.0 

0.072771 
0.070825 

1063.8 
1131  7 

I945-4 
2067.8 

44-. 

32-5 

67-5 

007 

255 

8-9 

32-2 

23-3 

0.068879 

3192-8 

£: 

27-5 
22.5 

72.5 

907 

85 

277 

7-8 

12.2 

18.3 
38-9 

10.5 
26.7 

0.066933 
0.064987 

1701.6 
1382.7 

3093.8 
2519.6 

47.. 

17-5 

82.5 

907 

241 

'5-5 

37-2 

21.7 

0.063041 

2427.8 

48.. 

12.5 

87-5 

907 

104 

14-4 

22.7 

8-3 

0.06:055 

1211.9 

22II.8 

49-  • 

7-5 

92.5 

907 

240 

18.9 

33-3 

14.4 

0.059149 

956.5 

1752.8 

5°  

2-5 

97-5 

907 

154 

20.5 

27.2 

6-7 

0.057203 

725.3 

1337-0 

The  test-pieces  were  usually  cast  in  iron  moulds  to  secure 
rapid  cooling. 

201.  External  Appearance  of  the  Bars. — The  following 
were  characteristic  features  of  the  bars  after  casting : 

(i)  A  regular  gradation  in  color  took  place  from  bar  No. 
I,  all  copper,  down  to  No.  8,  76.64  copper,  23.24  tin,  the  pol- 
ished surface  of  which  was  light  golden  yellow,  and  a  regular 
gradation  in  hardness,  No.  8  was  filed  with  great  difficulty. 

*  In  casting  bar  No.  32  (94.10  copper,  5.43  tin),  while  pouring  the  metal  into 
water  for  the  temperature  test,  an  explosion  took  place  which  broke  the  wooden 
vessel  holding  the  water,  and  threw  water  and  metal  about  with  great  violence. 

No.  30  was  cast  at  a  dazzling  white  heat.  On  pouring  a  small  portion  into 
water  to  obtain  the  temperature,  a  severe  explosion  took  place,  and  this  was  re- 
peated every  time  that  even  a  drop  of  the  molten  metal  touched  the  water.  After 
the  metal  remaining -in  the  crucible  had  cooled  considerably,  it  could  be  poured 
into  water  without  causing  explosions. 

It  might  be  supposed  that  the  result  of  casting  at  high  temperature  would  be 
to  make  .No.  30  a  bad  bar,  as  this  seems  to  be  indicated  by  the  experiments  of 
Major  Wade  on  gun-metal.  The  result,  however,  showed  the  contrary,  as  it 
proved  to  be  equal  to  any  bars  cast. 


326  MATERIALS  OF  ENGINEERING-NON-FERROUS  METALS. 

(2)  A  sudden  change  of  all  properties  took  place  at  bar 
No.  9 — 69.84  copper,  29.89  tin.     This  bar  was  silver-white  in 
color,  and  could  not  be  scratched  with  a  file.     Pieces  broken 
off  showed   a  conchoidal   fracture.      No.    10 — 68.58   copper, 
31.26  tin — was  similar  to  No.  9,  and  No.  II — 65.34  copper, 
34.47  tin — but  little  different. 

(3)  Another  change  of  color  and  properties  occurred  at 
No.   12 — 62.31   copper,  37.35  tin — which  bar  was  of  a  dark 
bluish-gray  color,  and  the  fracture  similar  to  that  of  granite 
or  other  hard  rock.     This  was  the  most  dense  alloy  of  the 
series.     No.  13 — 56.70  copper,  43.17  tin — was  similar  to  No. 
12,  but  lighter  in  color  and  a  little  softer. 

(4)  Bar  No.  14 — 51.62  copper,  48.09  tin — was  peculiar  in 
showing  a  marked  difference  in  the  two  ends  of  the  bar.     The 
upper  end  was  like  bar  No.  12,  while  the  bottom  was  of  a 
lighter  color,  granular  fracture,  and  so  soft  that  it  could  be 
cut  with  a  knife  like  a  piece  of  chalk. 

(5)  A  change  between  bars   No.   14  and   No.  20 — 25.85 
copper,   73.80   tin — occurred    gradually,  the   bars   becoming 
whiter  and  softer,  and  the  appearance  of  fracture  changing 
from  rough  and    stony  to  crystalline   or  granular.     No.   20 
could  be  cut   with  a  knife,   giving  a  short  chip   which  had 
slight  cohesion.     From  No.  20  to  No.  29  (all  tin)  the  soft- 
ness increased  gradually,  No.  21  giving  a  malleable  chip  on 
being  cut.     From   No.  24  to  No.  29  the  appearance  of  all 
bars  was  much  the  same,  differing  slightly  in  hardness,  and 
scarcely  at  all  in  color. 

No.  i  to  No.  8  were  likely  to  prove  of  value  where  strength 
was  required,  and  bars  No.  9  to  No.  1 8,  inclusive,  were  de- 
ficient in  ductility  as  well  as  in  strength,  and  for  all  practical 
purposes  (except,  perhaps,  extremely  limited  use  for  special 
purposes,  as  speculum  metal)  worthless, 

Nearly  all  of  the  bars  appeared  to  be  good  castings. 

202.  The  Behavior  of  the  Alloys  under  test  was  care- 
fully observed  and  a  journal  kept.  Thus  when  tested  by 
transverse  stress : 

Bar  No.  7  (80.95  copper,  18.84  tin),  the  strongest  of  the 
series/showed  little  ductility,  breaking  after  a  deflection  of 


- 


STRENGTH  OF  BRONZES.  $2? 

half  an  inch.  From  No.  8  to  No.  13  (23.24  to  43.17  tin)  in- 
clusive, there  was  a  regular  and  rapid  decrease,  both  in  strength 
and  ductility,  the  latter  being  the  weakest  bar  of  the  series, 
showing  only  about  *  g^th  of  the  strength  of  No.  7  and  a  de- 
flection of  only  0.0103  inch.  This  bar  gave  trouble  in  cast- 
ing by  breaking  in  the  mould.  Bar  No.  9  (69.84  copper, 
29.89  tin),  which,  in  appearance,  differed  remarkably  from 
No.  8  (76.64  copper,  23.24  tin),  had  less  than  f  ths  of  its  strength 
and  less  than  £th  of  the  strength  of  No.  7,  which  latter  differed 
only  10  per  cent,  from  it  in  composition  by  original  mixture, 
or  1 1  per  cent,  by  analysis.  Bars  No.  14  to  No.  20  (48.09  to 
73.80  tin)  inclusive,  showed  irregular  variation  in  strength 
and  ductility,  but  all  of  them  were  worthless,  the  best  having 
only  about  |th  of  the  strength  of  the  maximum,  and  a  deflec- 
tion of  only  o.i 23  inch  before  breaking.  Bar  No.  21  (23.35 
copper,  76.29  tin)  showed  considerably  greater  strength  and 
ductility  than  any  of  the  series  between  No.  8  and  No. 
20,  and  greater  strength  than  any  from  No.  8  to  No.  29  (all 
tin),  giving  what  may  be  called  a  second  maximum  point  of 
strength  in  the  series.  This  bar  had  a  cavity  extending 
throughout  nearly  its  whole  length, 

No.  21  to  No.  24  (76.29  to  88.47  tin)  had  higher  strength 
than  those  above  and  below  them  in  series,  showing  that  the 
second  maximum  point  of  strength  is  approached  by  bars 
having  a  difference  of  over  10  per  cent,  in  composition.  From 
No.  25  to  No.  29  (91.39  to  loo  tin)  there  was  a  somewhat  ir- 
regular decrease  of  strength  but  a  great  increase  of  ductility, 
bar  No.  29  (all  tin)  showing  the  maximum  ductility  of  the 
series  and  a  second  minimum  in  strength.  Bars  No.  26  to 
No.  29,  inclusive,  bent  without  breaking,  as  did  those  from 
No.  2  to  No.  6(1.90  to  12.73  tin)  at  the  other  end  of  the 
series. 

With  reference  to  the  relation  of  the  elastic  limit  to  the 
ultimate  transverse  resistance  from  bar  No.  I  to  No.  7  in- 
clusive, the  apparent  elastic  limit  occurred  at  from  35  to  65 
per  cent,  of  the  ultimate  resistance.  At  No.  8  this  limit  ap- 
proached nearly,  if  not  quite,  the  ultimate  resistance ;  and 
from  No.  9  to  No.  18  (29.89  to  61.32  tin)  jnjclnsive^tfee  two 

UNIVERSITY 


328   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

coincided,  z>.,  the  elastic  limit  was  not  reached  till  the  bar 
broke.  From  No.  19  (34.22  copper,  65.80  tin)  to  the  end  of 
the  series  (all  tin)  the  elastic  limit  was  again  reached  before 
fracture,  the  ratio  decreasing  to  No.  22  (20.25  copper,  79.63 
tin),  and  then  remaining  appreciably  constant  at  from  20  to 
30  per  cent,  to  the  end  of  the  series. 

The  relation  which  the  composition  bears  to  the  mechani- 
cal properties  of  strength,  ductility,  and  elastic  resistance  is 
thus  defined  with  tolerable  exactness. 

Bars  from  No.  I  to  No.  8,  inclusive,  had  considerable 
strength,  and  all  the  rest  were  worthless  for  all  purposes 
where  strength  is  required.  The  dividing  line  between  the 
strong  and  the  brittle  alloys  is  precisely  that  at  which  the 
color  changes  from  golden  yellow  to  silver  white,  viz.,  at  a 
composition  containing  between  24  and  30  per  cent,  of  tin ; 
alloys  containing  more  than  24  per  cent,  tin  are  comparatively 
valueless. 

The  journals  of  other  tests  give  very  similar  records  to 
those  just  quoted,  and  confirm,  generally,  the  deductions  which 
are  made  from  transverse  tests.  Of  the  two  bars  of  copper, 
No.  I  was  spongy  and  weak,  as  it  was  cast  in  sand ;  No.  30 
was  strong  arid  ductile. 

In  tests  by  compression,  many  pieces  were  compressed  to 
less  than  one-half  of  their  original  lengths,  the  resistance  to 
further  compression  always  increasing.  When  bending  took 
place,  the  piece  would,  in  some  cases,  take  such  a  position  as 
to  gradually  diminish  in  resistance,  the  pressure-plates  touching 
only  on  the  edges  of  the  upper  and  lower  surfaces  of  the  piece. 

The  actual  ''crushing  strengths"  of  the  ductile  metals, 
therefore,  cannot  be  stated ;  but,  for  purposes  of  comparison, 
the  crushing  strength  is  assumed  to  be  that  which  corre- 
sponds to  a  compression  of  one-tenth  of  the  original  length. 
In  the  table,  therefore,  the  figures  in  the  column  headed 
"  crushing  strength  "  represent,  in  the  cases  of  ductile  metals, 
the  loads  per  square  inch  necessary  to  produce  compressions 
of  10  per  cent,  of  the  original  lengths. 

All  brittle  alloys,  and  some  possessing  limited  ductility, 
No.  8  (76.64  copper,  23.24  tin)  to  No.  1 8  (38.37  copper,  61.32 


STRENGTH  OF  BRONZES.  329 

tin)  inclusive,  broke  suddenly  when  their  maximum  resist- 
ances were  reached,  and  the  figures  for  crushing  strengths  are, 
therefore,  actual  values.  In  these,  the  "  total  compressions 
produced  by  maximum  load  "  are  the  calculated  compressions 
at  the  instants  of  breaking.  In  other  cases,  the  figures  are 
total  compressions  actually  given  the  pieces  without  breaking 
them  and  include  the  shortening  of  the  piece  by  bending ; 
they  are  not  the  total  amounts  of  compression  which  might 
have  been  produced  had  the  test  been  continued  further. 

By  inspection  and  comparing  the  results  with  those  of 
transverse,  tensile,  and  torsional  tests,  some  important  facts 
are  observed.  Assuming  that  the  crushing  strength  of  a 
ductile  metal  is  the  load  necessary  to  produce  a  compression 
of  one-tenth,  and  that  of  a  brittle  metal  the  load  actually 
causing  fracture,  it  is  noted  that  the  maximum  and  minimum 
strengths  are  hot  found  in  the  compositions  which  exhibited 
maximum  and  minimum  strengths  by  the  other  methods  of 
test.  It  has  been  observed  that  the  relative  strengths  of  the 
alloys,  as  shown  by  the  other  three  methods  of  test,  are 
similar.  This  is  not  the  case  with  compressive  tests. 

The  maximum  crushing  strength  is  given  by  No.  9  (69,84 
copper,  29.89  tin),  which  gave  results  nearer  the  minimum 
under  the  other  tests.  The  minimum  strength  is  found  in 
tin,  which  was  superior  to  several  of  the  brittle  alloys  in  other 
methods  of  test,  which  alloys  greatly  surpassed  it  in  tests  by 
compression. 

The  compression  pieces,  No.  I  (all  copper)  to  No.  5  (90.27 
copper,  9.58  tin),  and  No.  30  (all  copper),  give  results  nearly 
alike.  From  No.  6  (87.15  copper,  18.84  tin)  to  No.  9  (69.84 
copper,  29.89  tin),  is  a  rapid  increase.  From  this  point  a 
decrease  takes  place  to  No.  29  (all  tin).  This  decrease  is 
somewhat  irregular.  It  would  be  necessary  to  make  a  number 
of  tests  before  attempting  to  explain  this  irregularity,  but  it 
may  be  a  peculiarity  of  these  compositions,  since  No.  12  was 
different  in  color  from  both  No.  II  and  No.  15,  and  had  the 
highest  density  of  the  series. 

Nos.  I  to  8  (all  copper  to  76.64  copper,  23.24  tin),  inclu- 
sive, were  turned  in  the  lathe  without  difficulty,  a  gradually 


33°  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

increasing  hardness  being  noticed,  the  last  named  giving  a 
short  chip,  and  requiring  frequent  sharpening  of  the  tool. 
The  turned  surface  was  perfectly  smooth.  The  color  varied 
from  copper-red  to  light  golden-yellow,  gradually  becoming 
lighter  with  increase  of  percentage  of  tin. 

Nos.  36  to  42  (43.99  copper,  55.91  tin)  inclusive,  were  tested 
with  their  original  section  unaltered,  as  they  were  too  brittle 
to  be  turned.  All  gave  trouble  in  setting  in  the  tension  machine, 
their  brittleness  and  hardness  being  so  great  that  the  grips 
of  the  machine  would  not  firmly  hold  them.  They  usually 
broke  in  the  grips,  and  the  figures  representing  strength  are 
in  many  cases  too  low. 

203.  Surfaces  of  Fracture. — After  the  tests  by  transverse 
stress,  pieces  were  cut  from  each  bar  showing  the  fracture. 
These  pieces  were  examined  by  Prof.  A.  R.  Leeds,  who  made 
the  following  report. 

No.  I  (all  copper). — Color,  copper-red,  altering  by  ex- 
posure to  air  into  purple  by  film  of  suboxide,  and  into  black 
by  film  of  oxide  of  copper. 

Surface  in  part  large  vesicular,  in  part  curvilinear  fibrous. 
Maximum  diameter  of  vesicles,  7  mm. ;  maximum  breadth  of 
fibres,  1.5  mm.;  length,  8  mm. 

No.  2  (97.89  copper,  1.90  tin). — Color,  red,  slightly  oxi- 
dized by  exposure.  Large  and  coarse  vesicular ;  maximum 
diameter  of  vesicles,  5  mm. 

No.  3  (96.06  copper,  3.76  tin). — Color,  bright  reddish-yel- 
low, with  faint  traces  of  black  oxide  from  exposure.  Surface, 
small  and  finely  vesicular. 

No.  4  (92.11  copper,  7.80  tin). — Color,  dull  reddish-yellow. 
Homogeneous.  Surface,  finely  arborescent. 

No.  5  (90.27  copper,  9.58  tin). — Color,  reddish-yellow,  with 
spots  of  dark  red  and  bright  yellow.  Surface,  not  homoge- 
neous, in  part  vesicular,  in  part  finely  fibrous. 

No.  6  (87.15  copper,  12.73  tin). — Color,  brass-yellow  in 
part,  in  part  bluish-white.  Surface,  not  homogeneous,  finely 
vesicular.  Fracture,  hackly. 

No.  7  (80.95  copper,  18.84  tin). — Color,  reddish-gray,  with 
brass-yellow  spots.  Surface,  reticulated  fibrous. 


S TRENG  TH  OF  BRONZES.  3  3 1 

No.  8  (76.64  copper,  23.24  tin). — Color,  reddish-gray.  Sur- 
face, faintly  vesicular ;  interior  of  vesicles  brass-yellow.  Fract- 
ure, irregularly  curved.  Lustre,  dull. 

No.  9  (69.84  copper,  29.89  tin). — Color,  grayish-white.  Sur- 
face, crystallization  prismatic,  diverging  from  centre.  Fract- 
ure, of  large  curvature.  Lustre,  glistening. 

No.  10  (68.58  copper,  31.26  tin). — Color,  grayish-white, 
more  white  than  the  preceding.  Surface,  crystalline  pris- 
matic, diverging  from  the  centre.  Fracture,  of  large  curva- 
ture. Lustre,  glistening. 

No.  1 1  (65.34  copper,  34.47  tin). — Color,  bluish-gray,  show- 
ing yellowish  spots  in  some  lights.  Surface,  interruptedly 
crystalline.  Fracture,  coarsely  rounded.  Lustre,  splendent. 

No.  12  (62.31  copper,  37.35  tin). — Color,  dark  bluish-gray. 
Surface,  laminated.  Fracture,  coarse  hackly.  Lustre,  splen- 
dent. 

No.  13  (56.70  copper,  43.17  tin). — Color,  bluish-white. 
Surface,  crystallization  eminent ;  crystals  prismatic  and 
diverging  from  centre.  Lustre,  splendent. 

No.  14  (51.62  copper,  48.09  tin). — Color,  bluish-white. 
Surface,  crystallized,  but  not  readily  apparent.  Fracture, 
coarse  angular.  Lustre,  splendent. 

No.  15  (47.61  copper,  52.14  tin). — Color,  grayish-white. 
Surface,  finely  granular.  Fracture,  waved.  Lustre,  glistening. 

No.  16  (44.52  copper  55.28  tin). — Color,  grayish-white. 
Surface,  laminated  granular.  Fracture,  coarsely  waved. 
Lustre,  glistening. 

No.  17  (42.38  copper,  57.30  tin). — Color,  grayish-white. 
Surface,  crystallization  finely  reticulated.  Fracture,  uneven. 
Lustre,  glistening. 

No.  1 8  (38.37  copper,  61.32  tin). — Color,  grayish-white. 
Surface,  crystallized,  but  not  readily  apparent.  Fracture, 
coarse  hackly.  Lustre,  bright. 

No.  19  (34.22  copper,  65.80  tin). — Color,  grayish-white. 
Surface,  crystallization  eminent,  prismatic,  and  diverging 
from  centre.  Prismatic  angle,  130°.  Sides  of  prism  doubly 
striated,  one  set  of  striae  parallel  to  edge  of  prism,  the  other 
at  an  angle  of  47°  with  the  former.  Lustre,  splendent. 


3 3 2    MA  TERIA LS  OF  ENGINEERING— NON-FERRO  US  ME  TALS. 

No.  20  (25.85  copper,  73.80  tin). — Color,  grayish-white. 
Surface,  crystallization  eminent,  prismatic.  Lustre,  splendent. 

No.  21  (23.35  copper,  76.29  tin). — Color,  grayish-white. 
Surface,  crystallized,  but  not  readily  apparent.  Fracture, 
hackly.  Lustre,  bright. 

No.  22  (20.25  copper,  79.63  tin). — Color,  grayish-white. 
Surface,  crystallization  not  large  but  eminent  ;  prismatic 
diverging  from  centre.  Prismatic  angle,  107°.  Lustre, 
splendent. 

No.  23  (15.08  copper,  84.62  tin). — Color,  grayish-white. 
Surface,  crystallization,  coarse  with  prismatic  faces,  divergent. 
Fracture,  jagged.  Lustre,  splendent. 

No.  24  (11.49  copper,  88.47  tin). — Color,  grayish-white. 
Surface,  crystallization  finely  reticulated.  Fracture,  hackly. 
Lustre,  dull  with  bright  reflections  from  scattered  crystalline 
faces.  Section,  distorted. 

No.  25  (8.57  copper,  91.39  tin). — Color,  grayish-white. 
Surface,  granular.  Lustre,  dull,  with  glistening  points. 
Section,  distorted  with  curved  edges. 

No.  26  (3.72  copper,  96,31  tin). — Color,  grayish-white. 
Surface,  rounded  granular.  Lustre,  dull. 

No.  27  (0.74  copper,  99,02  tin). — Color,  grayish-white. 
Surface,  usually  crystallization  feeble  with  undefined  pris- 
matic faces.  Lustre,  bright. 

No.  28  (0.32  copper,  99.46  tin).— Color,  grayish-white. 
Surface,  irregularly  waved.  Lustre,  dull. 

No.  29  (All  tin). — Color,  bluish  or  grayish-white.  Surface, 
slightly  vesicular  at  centre,  prismatic  at  edges.  Section, 
much  distorted.  Lustre,  bright. 

The  following  description  of  the  fractures  by  tensile  stress 
was  also  recorded  : 

No.  I  B  (all  copper). — Color,  copper-red,  with  a  purple 
film  of  sub-oxide  ;  surface,  in  part  large  vesicular,  in  part 
crystalline,  radiating  toward  edge. 

No.  2  A  (97.95  copper,  1.88  tin). — Color,  copper-red  ;  sur- 
face deeply  vesicular  ;  fracture,  uneven  ;  lustre,  dull,  with 
bright  points. 

Bar  No.  2  B  (97.83  copper,   1.92  tin). — Color,  copper-red, 


STRENGTH  OF  BRONZES.  333 

inclining  toward  yellow  ;  surface,  finely  vesicular ;  fracture, 
uneven  ;  lustre,  dull,  with  fine  bright  points. 

Bar  No.  3  B  (95.96  copper,  3.80  tin). — Color,  reddish-yel- 
low ;  surface,  finely  vesicular,  the  curved  surfaces  interrupt- 
ing; lustre,  dull. 

Bar  No.  4  B  (92.07  copper,  7.76  tin). — Color,  yellowish-red 
in  part,  in  part  reddish-yellow  ;  surface,  vesicular  ;  lustre,  dull. 

Bar  No.  5  A  (90.11  copper,  9.66  tin). — Color,  yellowish- 
red  ;  surface,  crystallization,  fibrous,  radiate,  finely  vesicular 
on  faces  ;  lustre,  dull. 

Bar  No.  5  B  (90.43  copper,  9.50  tin). — Color,  grayish-yel- 
ow  ;  surface,  coarse  vesicular  ;  fracture,  jagged  ;  lustre,  dull. 

Bar  No.  6  A  (87.15  copper,  12,69  tin).— Color,  bluish-white 
with  bright  yellow  spots  ;  surface,  confusedly  vesicular;  fract- 
ure, hackly  ;  lustre,  dull. 

Bar  No.  6  B  (87.15  copper,  12.77  tin)- — Color,  reddish-yel- 
low, with  bluish-gray  points,  producing  a  general  impression 
of  orange  ;  surface,  broadly  crystalline,  with  surfaces  of  pris- 
matic faces  finely  vesicular ;  lustre,  dull,  with  minute  bright 
points. 

Bar  No.  7  A  (80.99  copper,  18.92  tin). — Color,  grayish- 
white  with  yellow  points;  surface,  not  apparently  crystalline; 
fracture,  coarse  hackly ;  lustre,  dull. 

Bar  No.  8  B  (76.60  copper,  23.23  tin). — Color,  yellowish- 
gray  ;  surface,  vesicular,  with  smooth  intervening  faces ;  fract- 
ure, even  ;  lustre,  shining. 

Bar  No.  9  A  (69.90  copper,  29.85  tin). — Color,  yellowish- 
gray  to  bluish-gray  in  different  lights  ;  surface,  broadly-bladed 
prismatic,  and  diverging  from  centre;  fracture,  smooth;  lus- 
tre, splendent. 

Bar  No.  10  A  (68.58  copper,  31.26  tin). — Color,  yellow  to 
bluish-gray ;  surface,  broadly-bladed  prismatic  and  diverging 
from  centre  ;  fracture,  smooth ;  lustre  splendent. 

Bar  No.  11  A  (65.31  copper,  34.47  tin). — Color,  yellow  to 
bluish-gray;  surface,  crystallized,  but  not  readily  apparent ; 
fracture,  coarsely  waved  ;  lustre,  splendent. 

Bar  No.  12  B  (62.79  copper,  36.96  tin). — Color,  blue  ;  sur- 
face, coarsely  waved  and  pitted  ;  lustre,  splendent. 


334    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Bar  No.  13  A  (56.28  copper,  43.11  tin). — Color,  bluish; 
surface,  crystallization  eminent,  prismatic  blades  diverging 
from  centre  ;  fracture,  uneven ;  lustre,  splendent. 

Bar  No.  14  A  (62.27  copper,  37.58  tin). — Color,  bluish-gray 
in  part,  in  part  reddish-gray  ;  surface,  crystallized  but  not 
readily  apparent  ;  fracture,  uneven  ;  lustre,  dull. 

Bar  No.  14  B  (38.41  copper,  61.04  tm)- — Color,  bluish-gray  ; 
surface,  crystallized  but  not  readily  apparent  ;  fracture, 
coarsely  waved  ;  lustre,  splendent. 

Bar  No.  15  B  (47.49  copper,  52.29  tin). — Color,  bluish-gray 
to  grayish  white  ;  surface,  waved ;  fracture,  irregular ;  lustre, 
glistening. 

Bar  No.  16  B  (44.42  copper,  55.41  tin). — Color,  grayish- 
white  ;  surface,  crystallized  but  not  readily  apparent,  waved 
and  feebly  vesicular;  lustre,  glistening. 

Bar  No.  17  B  (38.83  copper,  60.79  tin)- — Color,  grayish- 
white  ;  surface,  finely  waved  vesicular ;  lustre,  shining,  with 
bright  points. 

Bar  No.  18  A  (43.37  copper,  56.37  tin). — Color,  grayish- 
white  ;  surface,  crystallization  prismatic,  with  waved  lines  on 
prismatic  faces;  lustre,  splendent. 

Bar  No.  18  B  (43.36  copper,  56.40  tin). — Color,  grayish- 
white  ;  surface,  crystallized  but  not  readily  apparent,  feebly 
vesicular  ;  fracture,  irregular  ;  lustre,  glistening,  bright  lines 
of  reflection  from  crystalline  faces. 

Bar  No.  19  A  (40.32  copper,  59.46  tin). — Color,  grayish- 
white  ;  surface,  crystallization  eminent,  prismatic ;  the  pris- 
matic faces  large  and  striated  ;  prismatic  angle,  91°  ;  lustre, 
splendent. 

Bar  No.  19  B  (40.24  copper,  59.44  tin). — Color,  grayish- 
white  ;  surface,  crystallization  eminent,  prismatic ;  lustre, 
splendent. 

Bar  No.  20  A  (26.57  copper,  73.08  tin). — Color,  grayish- 
white  ;  surface,  crystallization  eminent,  the  faces  in  part 
prismatic,  in  part  having  an  octahedral  aspect ;  lustre,  splen- 
dent. 

Bar  No.  20  B  (25.12  copper,  74.51  tin). — Color,  grayish- 
white  ;  surface,  crystallized  but  not  readily  apparent,  waved 


STRENGTH  OF  BRONZES.  335 

and  feebly  vesicular  fracture,  rough  ;  lustre,  glistening,  with 
bright  surfaces  of  reflection. 

Bar  No.  21  B  (33  89  copper,  75.68  tin). — Color,  grayish- 
white  ;  surface,  feebly  crystalline  and  vesicular ;  fracture, 
hackly  ;  lustre,  glistening,  with  bright  points. 

Bar  No.  22  A  (20.28  copper,  79.63  tin). — Color,,  grayish- 
white  ;  surface,  crystallization  eminent,  prismatic  faces  irre- 
gular ;  lustre,  splendent. 

Bar  No.  22  B  (20.21  copper,  79.62  tin). — Color,  grayish- 
white  ;  surface,  confusedly  crystalline,  with  prismatic  faces ; 
lustre,  splendent. 

Bar  No.  23  A  (15.12  copper,  84.58  tin). — Color,  grayish- 
white,  in  part  with  yellow  tarnish  ;  surface,  crystallization 
eminent,  broad  prismatic  faces,  radiate  ;  lustre,  splendent. 

Bar  No.  24  B  (11.48  copper,  88.50  tin). — Color,  grayish- 
white;  surface,  crystallized  fibrous;  fracture,  hackly;  lustre/ 
glistening,  with  bright  lines  of  reflection  from  edges  of  crys- 
tals. 

Bar  No.  25  A  (8.82  copper,  91.12  tin). — Color,  grayish- 
white  ;  surface,  irregular  and  feebly  vesicular  ;  lustre,  dull. 

Bar  No.  26  B  (3.74  copper,  96.32  tin). — Color,  grayish- 
white  ;  surface,  fibrous,  in  part  slightly  vesicular  ;  lustre,  dull. 

Bar  No.  27  A  (0.75  copper,  98.98  tin). — Color,  grayish- 
white  ;  surface,  fibrous  ;  fracture,  jagged  ;  lustre,  dull. 

204.  Records  illustrating  the  Methods  and  Results 
of  this  research  are  given  on  the  following  pages,  in  tabular 
form,  selected  from  the  mass  of  data  recorded  in  the  reports 
of  the  U.  S.  Board,  to  which  reference  may  be  made  for  other 
details.  Those  here  given  are  representative  of  the  work 
done  on  some  of  the  best  alloys  discovered  during  the  inves- 
tigation, but  do  not  by  any  means  include  all  the  useful 
compositions,  the  data  from  which  are  included  in  the  table 
of  summaries  of  all  methods  of  test  there  given.  These  tables 
of  records  cover  the  range  from  good  bearing  metal  to  bell- 
metal,  and  the  figures  given  are  fair  averages  for  such  alloys ; 
they  fall  considerably  below  figures  attainable  in  larger  work 
performed  by  trained  workmen. 


33^  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

TABLE   LXII. 

TESTS   BY   TENSILE   STRESS. 

No.  4  A.— Material :  Alloy.— Original  Mixture  :  92.8  Cu.  7.2  Sn.— Analysis, 92. 14  €11,7.84  Sn. 
— Dimensions:  Length,  5";  Diameter,  0.798". 


Load. 

Load   per 
square 
inch. 

Elongation 
in  5  inches. 

||| 

Load. 

Load  per 
square 
inch. 

Elongation 
in  5  inches. 

c  °  be 

III 

|il 

s 

Pounds. 

Poztnds. 

Inch. 

Pounds. 

Pounds. 

Inch. 

5,100 

10.200        , 

O.OI 

,0020 

14,610 

29,220 

o-37 

.0740 

8,000 
10,000 
10,760 

16,000 

20,000 

21,520 

O.O2 
0.03 
0.05 

.0040 

.0060 

.0100 

I4Bro°ke 
Diame 

29,300 
i£  inches  fro 
ter  of  fractu 

o-39 
m  C  end. 
red  section,  < 

.0780 

3.730  inch. 

11,410 

22,820 

O.O  ) 

.0180 

No  blowholes. 

o 

Set  0.08 

Tenacity  per  square  inch  of  original  sec- 

11,900 
12,800 

23,800 

25,600 

O.II 

0.14 

.0220 
.0280 

tion,  29,300  pounds  (2,090  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch  in  fractured  sec- 

13^40 

26,280 

0.21 

.0420 

tion,  35,000  pounds  (2,461  kgs.  per  sq.  cm.). 

14,000 

28,000 

0.27 

.0540 

No.  7  A. — Material:  Alloy. — Original  mixture:  80  Cu,  20  Sn. — Analysis:  80.99  Cu,  18.9280. 
— Dimensions  :  Length,  6"  ;  Diameter,  0.798". 


91850 

19,700 

O.OI 

.002 

Tenacity  per  square  inch  original  section, 

14.000 

16,800 

28,000 
33,600 

O.O2 

Broke  in 

.004 
middle. 

33,6^0  pounds   2,362  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch,  deducting  blow- 
hole, 34,139  pounds  (2.400  kgs.  per  sq.  cm.). 

Diameter  of  fractured  section,  0.7 

08  inches. 

One  blowhole,  irregular-shaped,  about  o.io 

inch  diameter. 

No.  33  B.— Material:  Alloy.— Original  mixture  :  87.5  Cu,  12.5  Sn.— Dimensions  :  Length,  5' 

Diameter,  0.798". 


1,200 

0.0025 

.0005 

24,000 

0.0905 

.0191 

2,000 

0.0052 

.OCIO 

200 

o'.o665 



3,000 

0.0097 

.0019 

26,000 

0.1040 

.0208 

4,000 

0.0139 

.0028 

28,000 

0.1271 

•0254 

6,000 

0.0206 

.0041 

200 

0.1063 

8,000 

0.0275 

.0055 

30,000 

0.1561 

.     .0312 

200 

—  o'.oooS  (?) 

32.000 

0.2007 

.0401 

10,000 

o  0330 

'.0066 

2OO 

o.  1811 

12,000 

0.0396 

.0079 

33,000- 

0.2270                

•  0454 

200 

0.0049 

33,200 

0.2432       i          

.0485 

14.000 

°-°473 

.0094 

16,000 

0.0541 

.0108 

Broke  in  middle. 

200 

0.0200 

Diameter  of  fractured  section,  0.770  inch. 

18,000 

0.0623 

.0125 

Tenacity  per  square  inch,  original  section, 

20,000 

200 

0.0709 

0.0421 

.0142 

33.200  pounds  (2,334  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  sec- 

22,000 

0.0793 

.0159 

tion,  35,648  pounds  (2,508  kgs.  per  sq.  cm.). 

STRENGTH  OF  BRONZES.  337 

TABLE    LXIII. 

TESTS    BY    COMPRESSIVE    STRESS. 

No.  31. — Material:  Alloy. — Original  mixture:  97.  5  Cu,  2.5  Sn.—  Analysis:  99.09  Cu,  0.87  Sn. 
— Dimensions:  Length,  2"  ;  Diameter,  0.625". 


c.J. 

c.J. 

""  bo 

c'£  j~ 

'*%* 

Load. 

Compres- 
sion. 

Load  per 
square 
inch. 

r\  *•*  "* 

:     Load. 

Compres- 
sion. 

Load  per 
square 
inch. 

_o  o£ 
£«Jl 

lal 

111 

u 

U 

Pounds. 

Inch. 

Pounds. 

Pounds. 

Inch. 

Pounds. 

150 

.0000 

16,000 

•3951 

52,152 

•T975 

2.000 

.00.8 

6,519 

.0009 

18,000 

.5176                58,671 

.2588 

4,000 

.0093 

13,038 

.0046 

20,000 

61  «;6 

65,188 

.3078 

6,000 

.0302 

J9'557       i     .0151 

22,000 

.7266 

71,700 

•3683 

8,000 

.0609 

26,075 

.0305 

24,000 

.8483               78,228 

.4242 

10,000 

.1077 

32,595 

•0539 

25,000 

.8801*             81,485 

.4100 

12,000 

.1662 

.0831 

14,000 

.2601      ' 

45,633 

.1300 

*  Wedge  cracked  off  at  the  top. 

No.  32. — Material :  Alloy. — Original  mixture:  92.5  Cu,  7.5  Sn. — Analysis  :  94.11  Cu,  5.43  Sn. 
Dimensions:  Length,  2"  ;  Diameter,  0.625". 


150 

.0000 

22,000 

.458<. 

71,709 

.2292 

2,000 

.0000 

6,5J9 



24,000 

•SIS! 

78.228 

•2575 

4,000 

.0000 

13,038 

26,000 

.5778 

84,747 

.2889 

6,000 

.0002 

19-557 

.0001 

28,000 

.6303 

91,266 

•3J97 

8.000 

.0108 

26,075 

.0054 

3O,OOO 

.7000 

97,780 

•3500 

IO.OOO 

.0511 

32,595 

.0255 

32,000 

•7499 

104,303 

-3749 

I2,COO 

.1219 

30,'  14 

.0609 

34.000 

.8033 

110,822   i   .4016 

i.t,coo 

.1937 

45,633 

.0968 

36,000 

.8447 

117,341     .4223 

16,000 

.2648 

52,152 

.1324 

38,000 

.8918 

123,860     .4459 

18.000 

•33'-o 

58,671 

.1655 

40,000 

•9330 

130,379   <  -4665 

20,000 

•3951 

65,188 

.1975 

No.  33. — Material:  Alloy. — Original  mixture:  87.5  Cu.  12.5  Sn. — Analysis:  88.4oCu,  11.59 
Sn. — Dimensions  :  Length,  2"  ;  Diameter,  0.625". 


150 

.OOOO 

24,000 

•  3234 

78,228 

.1617 

4,000 

.OOIt 

=  3,038 

.0007 

26,000 

•  3575 

84.747 

•1783 

6,000 

.0058 

19,557 

.0029 

28.000 

.4019 

91,266 

.2009 

8.000 

.0:70 

26,075 

.0085 

30.000 

.4412 

97.785 

.2206 

10,000 

•0374 

32,595 

.0187 

32,000 

•4815 

104,303 

.2407 

12,000 

.0711 

3Q,  '*4 

•0355 

1   34,ooo 

.5171 

110,822 

•  2585 

14,00? 

.1166 

45-633 

.0583 

!   3^,000 

•  5534 

117,341 

•  2767 

16,000 

1636 

52.152 

.0818 

38.00-) 

5905 

123,860 

.2952 

18,000 

20.000 

.2102 

.2564 

58.6^1 
65,188 

.1051 
.1282 

40,000 
42,000 

.6234 
.6^11 

I3°-379 
136,898 

•3"7 
•3305 

22,000 

.2991      7I-7°9     •I495 

j   44,ooo 

.6911    1  143,417 

! 

•3455 

22 


338    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE  LXIV. 


TESTS   BY   TR  AN  VERSE   STRESS. 


flo.  4.— Material :  Alloy.— Original  mixture  :  92.8  Cu,  7,2  Sn.— Dimensions  :  Length  between 
supports,  22"  ;  Breadth,  0.997"  \  Depth,  1.012". 


Load. 

Deflection,  A  . 

Set. 

Modulus  of 
elasticity. 

£-4/^(/>+<> 

Load. 

Deflection,  A. 

Set. 

Modulus  of 
elasticity. 

E=-—,ja(P+4) 
4  A  bd* 

Pounds. 
6 
10 

20 
30 
40 
60 
80 
100 

o 

125 
150 
175 

200 
O 
225 
250 
O 

275 
300 

o 

325 
350 

375 
400 
o 
425 
450 
475 
o 
500 

0 

525 
550 

0 

575 
o 
600 
o 

650 

0 

700 

Inch. 
0.0008 
0.0016 
o  .  0039 
0.007 

O.OIO 

0.013 
0.017 

0.020 

0.024 
O.O29 
0.034 
0.041 

0.045 
0.052 

0.057 
0.059 

0.063 

o  066 
0.072 

0.075 

0.079 

0.082 
0.087 

0.095 

O.  IO2 

0.106 

0.  112 

o.  124 

0.137 

Inch. 

Pounds. 
o 
750 
800 

0 

850 
900 

0 

T  950 

In  5  m. 
1,000 
In  5  m. 
o 
1,050 
tn  10  m. 

I,IOO 

In  10  m. 
o 

T,IOO 

In  3  m. 

1,200 

In  10  m. 

0 
1,200 

1,250 
In  10  m. 
In  30  m. 
15"  30-" 
o 
1,250 
1,300 
In  10  m. 
In  30  m. 

In  30  m. 

Break 
Modu 

Inch. 

0.173 
0.199 

0.232 
o  287 

0.348 
0.429 
0.491 
0.584 

0.620 
0.781 
0.858 
1.031 

1-053 

1.289 
1.384 
1.824 

T-935 
2.178 
2.281 
2.637 

2.638 
2.746 
2.911 
2.966 
3.226 
6.706 

ng  load,  / 
us  of  rupt 
R 
Rm-- 

Inch. 

O.O2O 

0.049 

o.  116 
°-379 
0.807 

10,408,413 
8,114,620 

5,267,855 

13,  396,335 

O.ODO 

I2,8l3,22/ 

0.000 

o.oojS 

3,314,847 

12,583,801 

o.ooo 

0.000 

13,274,439 

I3',8i7,'8o3 

2,240,640 

1-549 

14,263,420 

2-343 

Tray  reach 
supports. 
=  i,35opoui 
are, 

=  3,o74. 

0.0016 
0.0024 

0.0032 

0.0055 
0.0095 

13,677,484 
I3i464.3SS 

1,223,372 

ed  bottom  of 
ids. 

3)  =  48,731- 

12,548,648 

0.153 

11,853,945 

STRENGTH  OF  BRONZES. 


339 


TABLE    LXIV.— Continued. 

No  32.— Material :  Alloy.— Original  mixture:  92.5  Cu,  7.5  Sn.— Dimensions  :  Length 
between  supports,  /  =  22"  ;  Breadth,  b  =  0.956"  ;  Depth,  d  =  0.982". 


Load. 

Pounds. 
10 

20 

120 
1  60 
200 

3 
240 
280 
320 
360 
400 
3 

1 

600 

Deflection. 

A 

Set. 

Modulus  of 
elasticity. 

E-     Pi* 

Load. 

Deflection. 

A 

Set. 

Modulus  of 
elasticity. 

A  £  bd^ 

4  A  bd* 

Inch. 
0.0060 
0.0104 
0.0185 
0.0278 
0.0376 
0.0472 
o  0572 

Inch. 

Pounds. 

640 
680 
720 
760 
800 

840 
880 
920 
960 

1,000 

1,040 

Bar  ben 
Break  i  i 
of  3*' 

Inches. 

0.2095 
0.2365 
0.2^67 

0.6031 

Inches. 
0.0:55 

6,357,759 
8,  4^i,  7^5 
9,384,450 
9,967,673 
10,281,341 

10,564,538 
10,70^,500 
10,692,594 
10,768,738 
10,644,211 

10,501,656 
10,161,429 
9,961,177 
9,579,  17l 
8,087,663 

7,957,281 

6,030,003 

3,900,466 

0.0035 

o  0413 

0.0668 
0.0769 
0.0880 
0.0983 
0.1105 

o  .  6202 

0.0427 
1.3217 
'.74 
2.13 
2.63 
3.78 

t  to  a  defle 
ig  load  (or 
')  i,  080  po» 



0.0145 
Beam  sinks 

1,380,404 

0.1232 
0.1389 

o.i535 
0.1719 
0-1963 

840,132 
3.40                  
:tion  of  8"  without  breaking, 
the  load  causing  deflection 
inds. 

0.0577 

0.206=; 

Resistance  decreased  in  2™  to  586  pounds. 
Resistance  decreased  in  ih  48'"  10562 pounds. 


Rm  =  2,718. 


No.  7. — Material :  Alloy. — Original  mixture :   So  Cu,  20  Sn. — Analysis :  80.95  Cu,  18.84 
Dimensions:  Length  between  supports,  22"  ;  Breadth,  0.998"  ;  Depth,  i.on. 


100 

125 

J5^> 
*75 

200 

O 

225 
250 

275 

300 

3 
325 
350 
375 
400 

0 

425 
450 
475 
500 
o 
525 
550 
575 
600 

0 

625 
650 
700 

0 

750 
800 

o 

850 

o.02<; 
0.028 

°-°33 
0.037 
0.043 

0.045 
0.051 
0.057 
0.063 

0.069 
0.073 
0.077 
0.081 

0.083 
0.087 
0.094 
0.098 

o.  03 
o.  05 
o.    14 

0.    22 

0.128 
0.132 
0.140 

o-JSS 
0.167 

0.172 

0.0024 

K>,737,827 
11,891,996 
12,045,639 
12,487,468 
12,245,726 

,00 
o 

950 

1,000 

o 

1,050 

0 
1,100 
1,200 

o 
1,300 

0 

1,400 

0 

1,500 
o 
1,600 

0 

1,700 

0 

T  Il6s<L 

In  15  h 

0 

1,520  ' 

ffift* 

Break 
Modul 

0.184 
0.192 

0.201 
O.2O9 
0.219 

o.  256 

0.285 
0.320 
0.360 

0-4T5 
0.470 

0.510 
0-537 

0.469 
Broke  i 
pound  of 
ng  load,  i 
us  of  rupti 

R  =  -\ 
26 

Rm  =  3,9 

0.0103 

12,681,589 

0.012 

12,893,200 

o  013 

0.026 
0.039 
0.055 
0.075 
0.099 
0.126 

13,012,118 
12,139,743 

11,810,161 

12,855,428 

0.0039 

",455,356 



12,517,091 

11,325,050 

0.0047 

12,874,176 

10,783,714 
9,976,527 

9,355,254 
9,202,114 

0.0063 

13,274,787 

0.169 



0.0063 

12,779,097 

o  seconds  after  putting  on 
the  weight. 
750  pounds, 
are, 

^y(/>+  3)  =  56,7i3. 
87. 

0.0039 

12,979,791 

0.0063 

12.426,896 

j 

340  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE    LXIV.— Continued. 

No.  33.— Material :  Alloy.— Original  mixture:  87.5  Cu,  12.5  Sn.— Dimensions :  Length  be- 
tween supports,  22";    Breadth,  0.973";    Depth,  o. 977". 


Load. 

Deflection. 

A 

Set. 

Modulus  of 
elasticity, 
Pfi 

Load. 

Deflection. 

A 

Set. 

Modulus  of 
elasticity. 
P*_ 

4  A  bd* 

4*M» 

Bounds. 
10 

20 
40 
80 
120 

160 

200 

3 
240 
280 
320 
360 
400 

3 
440 
480 
520 
560 
600 

640 
680 
720 
760 
800 

840 

880 
920 
960 

Inches. 
0.0042 
0.0075 
0.0125 
0.0236 
0.0322 
0.0409 
0.0508 

0.0606 
0.0701 
0.0793 
0.0890 
0,0580 

o.  1071 
0.1168 

Inches. 

Pounds. 
1,000 

Inches. 
0.3245 

Inches. 

3 
1,040 
i,  080 
1,200 
1,160 

1,200 

I,2OO 
I,240 

!    1,280 
1,300 
j    1,320 

0.3611 
0-3959 
0-4493 
0.5122 
0.5727 

0.0910 

9,387,752 
9,969,873 
0,603,633 
1,478,087 
I,549,89I 

1,618,503 

i,7i7,949 
1,838,275 
1,869,273 

',974,171 

8,002,946 



6,147,034 

0.0049 

0.2827 

0.5892 
o-6475 
0.7485 
0.8111 
0.8701 
o  9892 

0.0036  (?) 



12,052,435 

1,400 
1,440 
,480 

i          'SA° 
,500 

,630 
,640 
,680 

,70  3 

3 
1,700 
Bar  br 
Breaki 

Modul 

1.1419 
1.3032 
1.4878 
1.6700 
1.8500 

2.1000 
2.4500 

3.  looo 

3.5000 

oke  after  a 
ng  load,  i, 

us  of  rupt 

"2.81" 

deflection  of 
700  pounds 

ure,  R  -  -^ 

•20 

Rm  =  4,2 

3,596,760 

2,235,  '79 
1,424,927 

0-1335 
0.1461 

12,127,844 
12,047,936 

O.OII2 

0.1568 
0.1678 
0.1800 

°-I933 
0.2074 

0.2269 
0.2475 
0.2716 
0.2964 

11,888,540 

slowly. 

Beam  sinks 

0.0284 

",3i5,997 

about  4". 

y 

-p  =  60,403  Ibs. 
*6. 

9,937,327 

No.  34.—  Material  :  Alloy.—  Original  mixture:  82.5  Cu,  17.5  Sn.—  Dimensions  :  Length  be- 
tween supports,  22";  Breadth,  0,950";   Depth,  0.970". 

1  20 
160 
200 

10 

240 
•280 
320 
360 
400 

10 

440 
480 

520 

560 

600 

10 

720 
760 

800 

Resistan 

10 

840 
880 
920 
960 

0.0316 
0.0405 
0.0481 

0.0560 
0.0646 
0.0729 
0.0834 
0.0881 

0.0940 
o.  1027 
0.1099 
0.1174 
0.1265 

0.1340 
0.1409 
O.M73 
0-1549 
0.1631 
ce  decreas 

0.1702 
0.1790 
0.1873 
0-1959 

11,659,056 
12,129,260 
12,765,982 

I,ooo 

JO 

1.040 
,080 

,120 
,100 
,200 
,240 
,280 

1,320 
1,360 

1,400 

10 

1,520 
1,  600 

10 

1  ,  720 

1,  800 
1,840 

Brok< 
30  secoi 
after  re 
Breal 

Modu 

0,2060 

.0,2157 
0.2264 
0,2377 
0,2472 
0.2614 
0,2728 
0.2852 
0,3003 
0,3175 
0-333° 

0.3880 
0,4393 

o,  S247 
0,5757 
0,6125 

:  suddenly 
ids  after  pi 
ading  the  c 
:ing  load,  i 

lus  of  rup< 

14,903,838 

0.0035 

0.0098 

14,802,137 

13,158,079 
I3,307,4T7 
*3,476,957 
i3-747,253 
13,939,699 

T4,  371,235 
14,349,611 
14,526,967 
14,644,993 
14,562,305 

14.663,731 
14,817,235 
15,007,180 
15,063,694 

!5,o59,3i8 
to  788  pounds, 

15,152,664 
15,093,815    | 
15,080,625     i 
15,045,481 

14,466,320 

!3,495,466 



0.0035 

0.0436 

12,055,389 

0.0028 

2d  in  i9h  45™ 
0.0047 

0-0935 

with  a  ringi 
atting  on  the 
leflection. 
,840  pounds. 

ture,  R  =  -  - 

2    I 

^  =  4,6 

1^,064,370 

9,223,187 

ng  sound  about 
strain,  and  just 

PI 

--2  =  67,930. 

75- 

STRENGTH  OF  BRONZES.  341 

205.  Final  Results. — The  following  table  exhibits  the 
results  of  the  whole  investigation  in  a  compact  form  which 
permits  ready  comparison  of  data. 

The  average  results  obtained  by  test  of  the  copper-tin 
alloys,  enable  the  engineer  to  reach  tolerably  definite  conclu- 
sions relative  to  their  value  in  construction.  The  results  are 
given  as  obtained  by  the  four  principal  methods  of  stress. 
They  are  very  variable,  and  this  variability  is  due  not  only 
to  the  variation  of  composition  of  the  alloys,  but  also  to  their 
differences  of  physical  structure,  and  is,  therefore,  to  some 
extent,  accidental. 

General  conclusions  may,  nevertheless,  be  deduced  and 
the  principal  facts  revealed  by  test,  and  these  conclusions 
are  also  most  unmistakably  exhibited  by  the  diagrams  pre- 
sented in  this  and  preceding  articles. 

The  figures  given  by  the  tests  have  been  plotted  in  the 
form  of  curves  having  for  their  ordinate  the  resistance  ob- 
served and  for  their  abscissas  the  distortion  of  the  given  test- 
piece.  These  curves  exhibit  the  method  of  variation  of  re- 
sistance with  progressing  change  of  form,  and  constitute 
"  strain  diagrams  "  which  exhibit  to  the  eye  every  important 
quality  of  the  material. 


342   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 


Q       5 
*      * 


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COMPRES- 
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343 


344  MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS 

206.  Strain-Diagrams,  obtained  from   tests  determining 
tenacity  of  the  bronzes,  are  given  in  the  accompanying  figure 
as  derived  from  experiments  upon  the  first  series  of  copper- 
tin  alloys,  No.  I,  pure  copper,  to  29,  pure  tin,  inclusive.     The 
curves  marked  A  are  from  the  upper  end   of  the   bar  and   B 
from  the  lower  end. 

These  curves  may  evidently  be  divided  into  three  classes : 
viz.,  those  which  are  very  rigid  and  brittle,  as  7  A,  7  B  (cop- 
per, 80,  bell-metal),  those  which  are  very  ductile  and  mallea- 
ble but  soft  and  weak,  as  Nos.  26  to  29  (tin,  95  to  100) 
inclusive  ;  and  those  which  combine  strength  and  ductility 
and  possess,  therefore,  great  resilience,  as  Nos.  2,  3  and  4 
A  (copper,  93  to  98,  gun-metals).  All  intermediate  qualities 
may  be  obtained,  but  these  are  typical  and  the  most  valuable 
of  these  compositions  are  evidently,  for  general  purposes, 
those  belonging  to  the  last  class,  and  of  which  the  strain- 
diagrams  lie  between  the  extreme  qualities,  one  set  of  which 
He  near  the  axis  of  abscissas,  while  the  other  set  lie  nearer  the 
axis  of  ordinates.  For  some  purposes,  as  when,  for  example, 
it  is  desirable  to  secure  a  high  elastic  limit  as  well  as  moderate 
toughness,  alloys  like  ordnance  bronzes,  Nos.  4,  5,  6  (copper, 
86  to  93),  which  are  stiff  and  strong,  although  not  very  ductile, 
may  be  chosen.  Cases  may  even  arise,  although  certainly 
not  often,  in  which  the  rigidity  of  bell-metal,  No.  7  (copper, 
80),  may  make  that  alloy  valuable  in  consequence  of  its 
high  elastic  limit,  notwithstanding  its  great  deficiency  in 
ductility. 

207.  The  Tenacities  of  the  valuable  class  of  these  metals 
range  not  far  from  30,000  pounds  per  square  inch  (2,109  kil°gs- 
per  sq.  cm.),  the  strength  increasing  somewhat  with  the  pro- 
portion of  tin  up  to   1 8  per  cent.     Within   that  range,  the 
expression 

T  —  30,000  +  i  ,000  /, 


in  which  T  is  the  tenacity  and  /  the  percentage  of  tin,  may 
be  taken  to  represent  a  maximum  which  selected   materials 


STRENGTH  OF  BRONZES. 


345 


346   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

and   careful  fluxing  should    enable  the  engineer  to  secure. 
Two-thirds  these  values,  or 

T  —  20,000  +  700  t, 

should  be  expected  as  a  minimum.     In  metric  measures,  the 
two  values  would  become,  nearly, 

T    —  2,100  +  700  /,  as  a  maximum  ; 
Tm  =  1,400  +  500  t,  as  a  minimum. 

The  ductility  should  be  at  least  10  per  cent,  for  the  best 
alloy,  and  must  be  expected  to  be  too  slight  to  be  counted 
upon  when  the  proportion  of  tin  exceeds  20  per  cent,  unless 
this  percentage  rises  to  a  very  high  figure,  as  from  90  per 
cent,  upward,  when  it  again  becomes  considerable. 

The  modulus  of  ultimate  resilience  obtained  by  multiply- 
ing two-thirds  the  tenacity  by  the  extension  of  a  piece  one 
unit  in  length  should  be,  in  foot-pounds,  for  the  more 
valuable  alloys,  not  less  than  3,000  foot-pounds  or  250 
foot-pounds  per  cubic  inch  (or  not  far  from  2.5  kilogram- 
metres  per  cubic  centimetre)  for  good  materials,  and  two- 
thirds  this  value  for  ordinary  work.  The  elastic  resilience  is 
not  to  be  expected  to  exceed  5  foot-pounds  per  cubic  inch  (or 
about  0.05  kilogram-metres  per  cubic  centimetre). 

The  plate  only  exhibits  one  of  the  two  sets  of  strain- 
diagrams,  and  a  less  favorable  representation  of  the  quality  of 
these  alloys  than  would  be  obtained  from  tests  of  specially 
prepared  and  carefully  fluxed  specimens,  such  as  may  be 
secured  when  needed. 

The  alloys  containing  from  75  down  to  25  per  cent,  copper 
are  stone-like,  inelastic,  brittle  and  worthless  for  the  work  of 
the  engineer,  their  strain-diagrams  are  straight  lines  and  do 
not  appear  in  the  figure. 

A  moderately  well  defined  "elastic  limit"  is  seen  to  exist 
with  many  of  the  harder  of  these  alloys,  as,  e.g.,  Nos.  3,  4,  5 
and  6  (copper,  85  to  95). 

208.  Compression  Strain-diagrams  are  exhibited  in 
Figure  10  which  are  obtained  from  the  same  set  of  alloys  as 


STRENGTH  OF  BRONZES. 


347 


s    f    a 


MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

were  used  in  the  preparation  of  the  tension  diagrams  shown 
in  the  preceding  illustration. 

The  alloys  do  not  hold  precisely  the  same  order  in  com- 
pression as  in  tension  ;  but  the  same  general  facts  are 
observable.  The  most  resilient  (ultimate)  metals  are  as 
above,  Nos.  I  to  7  and  30  (copper,  80  and  upward) ;  the  most 
malleable  are  Nos.  25  to  29  (copper,  10  or  less),  and  the  most 
rigid  are  Nos.  9,  10,  11  (copper,  65  to  70). 

No.  9  (copper,  70)  excels  enormously  in  strength  and  in 
elastic  resilience,  and  in  elastic  resistance ;  No.  8  (copper, 
75)  is  a  very  resilient  alloy,  also  ;  Nos.  6  and  7  (copper,  80  to 
86)  excel  in  ultimate  resilience,  or  power  of  resisting  shocks 
great  enough  to  deform  the  piece.  Gun-bronze,  No.  5  (c°p- 
per,  90),  is  evidently  one  of  the  best  of  these  alloys. 

Some  of  the  singular  variations  seen  in  several  of  the 
diagrams  are  probably  due  to  accidental  peculiarities  of  de- 
formation of  the  test  piece ;  possibly  all  may  be  so. 

Elastic'limits  are  not  as  well  defined  here  as  in  the  tension 
diagrams,  and,  in  the  hard  alloys,  are  either  obscure,  as  in  No. 
7  (copper,  80),  or  coincide  with  the  point  of  rupture,  as  in 
Nos.  9-15  (copper,  45  to  70). 

Comparing  the  two  sets  of  diagrams,  it  is  seen  that,  for 
members  in  tension,  for  bolts,  sheet  metal,  ordnance,  in  fact 
for  the  majority  of  all  common  purposes,  the  best  alloys  are 
those  lying  very  near  the  copper-end  of  the  series  and  con- 
taining from  2  to  10  per  cent,  of  that  metal,  and  the  less  as 
the  method  of  attack  includes  the  action  of  shock  to  a  greater 
extent.  For  compression,  more  tin  is  advisable  (10  to  15  per 
cent.)  if  shock  occurs,  and  it  may  be  justifiable  to  reduce  the 
copper  to  70  per  cent.,  even  if  the  load  is  applied  absolutely 
without  jar,  and  maximum  tenacity,  simply,  is  sought. 

209.  Transverse  Tests  of  the  copper-tin  alloys  give 
strain-diagrams  such  as  are  seen  in  Figure  II.  Compositions 
approaching  copper,  80,  tin,  20,  exhibit  the  greatest  strength 
under  this  form  of  load. 

Those  having  less  tin  (6  to  10  per  ceni..)  as  Nos.  4,  5 
(copper,  93  ;  copper,  90),  are  evidently  vastly  better  to  resist 
the  shock  of  suddenly  applied  loads  and  safer  against  accident ; 


STRENGTH  OF  BRONZES. 


349 


35O  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

while  those  consisting  principally  of  tin  are  soft  and  very 
ductile  and  malleable,  as  already  seen. 

210.  Comparison  of  Resistances.— By  inspection  of  the 
curves,  it  will  be  seen  that  the  curves  of  tensile  and  torsional 
strength  agree  very  closely,  the  torsion  curve  being  laid  down 
to  such  a  scale  that  one  foot-pound  of  torsional  moment  has 
the  same  measure  as  200  pounds  tenacity.  The  curve  of 
transverse  strength  is,  in  form,  similar  to  those  of  tension  and 
torsion  (one  pound  modulus  of  rupture  corresponding  to 
one  pound  tenacity),  but  the  ordinates  of  the  curve  are  usually 
much  greater  than  in  the  two  latter. 

The  curve  of  compression  strength  is  very  unlike  either  of 
the  others.  Laid  down  to  the  same  scale  as  that  of  tenacity, 
the  ordinates  of  the  curve  are  much  higher,  showing  that  the 
compression  resistances  of  the  copper-tin  alloys  are  much 
greater  than  their  tenacities.  The  maximum  compression 
strength  is  reached  by  one  of  the  brittle  alloys,  the  tenacity 
of  which  was  not  far  from  the  minimum. 

The  tensile  and  compressive  resistances  of  the  alloys  are 
in  no  way  related  to  each  other ;  the  torsional  strength  is 
very  nearly  proportional  to  the  tensile  strength.  The  trans- 
verse strength  may  depend,  in  some  degree,  upon  the  com- 
pressive strength,  but  it  is  much  more  nearly  related  to  the 
tensile  strength,  as  is  shown  by  the  general  correspondence 
of  the  curve  of  transverse  with  that  of  tensile  resistance. 
The  modulus  of  rupture,  as  obtained  by  the  transverse  tests, 
is,  in  general,  a  figure  between  those  of  tensile  and  compres- 
sive resistance,  but  there  are  a  few  cases  in  which  it  is  larger 
than  either,  indicating  an  approach  to  the  condition  suggested 
in  forming  the  equations  already  given. 

The  strength  of  the  alloys  at  the  copper  end  of  the  series 
increases  rapidly  with  the  addition  of  tin,  up  to  about  4  per 
cent.  Transverse  strength  continues  to  increase  up  to  about 
1^/2  per  cent,  of  tin;  while  the  tensile  and  torsional  resist- 
ances also  increase,  but  very  irregularly,  to  the  same  point. 
As  this  irregularity  corresponds  to  the  irregularity  of  the 
curve  of  specific  gravities,  it  is  probably  due  to  porosity,  and 
might  not  be  seen  in  sound  castings. 


STRENGTH  OF  BRONZES.  351 

The  maximum  point  of  the  three  curves  is  reached  at  about 
the  same  point,  viz.,  at  the  alloy  containing  82.70  copper, 
17.34  tin. 

From  the  point  of  maximum  strength,  the  three  curves 
drop  rapidly  to  alloys  containing  about  27.5  per  cent,  of  tin, 
and  then  more  slowly  to  37.5  per  cent.,  at  which  point  nearly 
the  minimum  strength  is  reached.  The  compression  curve 
reaches  its  maximum  between  these  points.  The  alloys  of 
minimum  strength  are  found  from  3.75  per  cent,  tin  to  52.5  per 
cent.  tin.  The  absolute  minimum  is  probably  about  45  per 
cent,  of  tin. 

From  52.5  per  cent,  of  tin  to  about  77.5  per  cent,  tin 
there  is  a  slow  and  irregular  increase  in  strength  to  the  point 
which  has  been  called  the  second  maximum. 

From  77.5, per  cent,  tin  to  the  end  of  the  series,  or  all  tin, 
the  strengths  slowly  and  somewhat  irregularly  decrease,  the 
second  minimum  being  reached  at  the  end  of  the  curve. 

All  alloys  containing  more  than  25  per  cent,  tin  are  prac- 
tically worthless  for  all  purposes  demanding  strength,  the 
average  strength  of  these  alloys  being  only  about  one-sixth  of 
the  average  of  those  containing  less  than  25  per  cent,  of  tin. 

Maximum  strength  is  associated  with  a  peculiar  color,  a 
reddish  or  pinkish  gray,  which  marks  the  change  from  the 
ductile  to  the  brittle  alloys,  and  occurs  between  the  percent- 
ages of  tin  which  give  a  silver-white  alloy  in  which  no  trace 
of  copper  could  be  detected  by  the  eye,  and  the  reddish- 
yellow  to  yellowish-gray  alloys  like  No.  6  (lower  end  of  bar) 
and  No.  33. 

The  results  of  these  tests  do  not  seem  to  corroborate  the 
theory  that  peculiar  properties  are  possessed  by  the  alloys 
which  are  compounded  of  simple  multiples  of  their  atomic 
weights  or  chemical  equivalents,  and  that  these  properties 
are  lost  as  the  compositions  vary  more  or  less  from  this 
definite  constitution.  It  does  appear  that  a  certain  percentage 
composition  gives  a  maximum  strength  and  another  certain 
percentage  a  minimum,  but  neither  of  these  compositions  is 
represented  by  simple  multiples  of  the  atomic  weights. 

There  appears  to  be  a  perfectly  regular  law  of  decrease 


352   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


STRENGTH  OF  BKCNZES.  353 

from  the  maximum  to  minimum  strength  which  does  no? 
have  any  relation  to  the  atomic  proportions. 

211.  Total  Resilience,  or  the  product  of  the  mean  resist- 
ance into  the  distance  through  which  the  resistance  acts,  is 
the  work  done  in  breaking  a  piece  of  metal.  For  tensile  stress, 
it  is  equal  to  the  mean  resistance  multiplied  by  the  total 
elongation  ;  for  transverse  stress  it  is  the  mean  resistance 
multiplied  by  the  total  deflection,  and  for  torsional  stress  it  is 
the  mean  resistance  of  the  specimen  as  measured  by  the  mean 
ordinate  of  the  autographic  strain  diagram,  expressed  in  foot- 
pounds of  torsional  moment,  or  pounds  acting  at  the  radius 
of  one  foot  multiplied  by  the  distance  through  which  this 
moment  is  exerted  as  measured  by  the  total  abscissa  of  the 
diagram,  and  reduced  to  feet  traversed  by  the  resistance.  Its 
values  are  given  elsewhere. 

The  total  resilience  under  transverse  stress  was  calculated 
from  the  curves  of  deflections  by  transverse  stress,  the  area 
of  the  curve  being  directly  proportional  to  the  resilience,  the 
ordinates  representing  resistances  and  the  abscissas  deflec- 
tions. The  results  are  reduced  to  foot-pounds  of  work.  In 
the  cases  of  bars  which  bent  to  a  deflection  of  more  than  3^ 
inches  (8.9  cm.)  without  breaking,  the  resilience  within  that 
limit  of  deflection  was  taken. 

The  torsional  resilience  was  calculated  from  the  area  of 
the  autographic  strain-diagram  and  reduced  to  foot-pounds 
of  work. 

The  resilience  under  tensile  stress  was  not  determined. 

Referring  to  the  plates  of  curves  of  resistances,  it  will 
be  found  that  resilience  bears  a  very  close  relation  to 
ductility,  the  curves  being  nearly  similar,  except  in  those  por- 
tions of  the  curves  representing  the  alloys  which  bent  with- 
out breaking  under  transverse  stress,  and  of  which  the  trans- 
verse resilience  is  taken  only  within  a  deflection  of  3^ 
inches. 

The  maximum  torsion  resilience  is  given  by  No.  3  (96.06 
copper,  3.76  tin),  one  of  the  most  ductile  of  the  strong  alloys. 
No.  33  (88.40  copper,  11.59  tm)  gave  maximum  transverse  re- 
silience within  the  deflection  of  3^  inches,  being  the  strong- 
23 


354  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 

est  alloy  which  reached  that  deflection  without  breaking,  but 
its  total  resilience  is  less  than  those  of  the  more  ductile  bars, 
v/hich  bent,  without  breaking,  to  deflections  of  more  than  8 
inches. 

From  the  bar  which  gave  maximum  total  resilience  a  rapid 
decrease  occurs  to  No.  8  (76.64  copper,  23.24  tin).  From  No. 
8  to  No.  20  (35.85  copper,  73.80  tin)  all  bars,  with  one  excep- 
tion, show  total  resiliences  so  small,  compared  with  the  maxi- 
mum, that  the  curve  of  resilience  between  these  points  ap- 
proaches the  bottom  line  of  the  plate  so  closely  that  it 
apparently  coincides  with  it.  The  figures  for  transverse  re- 
silience agree  with  those  of  torsional  resilience  between  these 
points. 

From  No.  20  to  No.  28  (0.32  copper,  99.46  tin)  there 
is  a  gradual  increase  of  the  total  resiliences  to  the  (t  second 
maximum." 

The  alloys  which  are  of  most  value  to  the  engineer  are 
evidently  those  containing  less  than  20  per  cent,  tin,  and,  for 
the  great  majority  of  purposes,  gun-bronze  (copper  89.90)  and 
the  alloys  containing  rather  less  tin  are  likely  to  prove  best ; 
while  those  containing  from  10  to  15  per  cent,  tin  are  evi- 
dently to  be  chosen  where  hardness,  combined  with  strength, 
must  be  secured.  Alloys  of  these  metals  containing  from  30 
to  70  per  cent,  of  either  are  rigid,  brittle,  and  valueless  for 
the  ordinary  purposes  of  the  engineer,  although  some  of  them 
may  have  use  for  special  work. 

The  phenomenon  of  decrease  of  set  with  time  was  observed 
for  the  first  time  with  No.  47.  On  relieving  the  bar  of  all 
pressure  except  that  due  its  own  weight,  and  except  a  very 
slight  pressure  (a  few  ounces)  to  insure  that  the  pressure-block 
actually  touched  the  bar  and  was  not  raised  from  it,  the  scale- 
beam  balanced  at  5  pounds,  and  the  reading  of  the  set  was 
made.  While  reading  the  set  the  scale-beam  was  observed 
to  rise,  indicating  increase  of  resistance  to  deflection,  as  it  had 
similarly  been  observed  to  drop  when  resistance  to  stress  took 
place.  A  number  of  observations  of  this  increase  of  resist- 
ance to  the  permanent  deflection  were  made,  and  also  of  the 
decrease  of  set,  as  measured  by  running  back  the  pressure- 


S  TKENG  TH  OF  BRONZES. 


screw  till  the  scale-beam  again  balanced  at  5  pounds,  and 
taking  additional  readings.  The  result  of  these  observations 
showed  that  in  one  observation  of  39  minutes  the  resistance 
of  the  bar,  as  measured  by  the  scale-beam,  increased  18  pounds^ 
and  that  in  2  hours  20  minutes  the  set  decreased  the  amount 
of  0.0239  inch. 

This  fact  of  the  decrease  of  set  with  time  has  since  been 
confirmed  by  a  large  number  of  tests  made  on  the  same  ma- 
chine, and  it  has  also  been  observed  by  other  experimenters. 
It  indicates  that  what  has  been  hitherto  called  the  "perma- 
nent set  "  of  metals  is  in  reality  not  entirely  permanent,  but 
is  partially,  at  least,  temporary,  a  fact  already  well-known. 

212.  Specific  Gravity.  —  The  curve  of  specific  gravities 
(Fig.  13)  shows  considerable  regularity,  indicating  that  the 
densities  of  the  alloys  follow  a  definite  law. 

The  alloys  containing  less  than  25  per  cent,  of  tin  show 
irregular  variation  in  specific  gravity  due  to  porosity.  The 
figures  obtained  are  the  densities  of  castings,  and  not  of  the 
metals  themselves,  as  they  might  be  determined  in  fine  pow- 
der, or  from  metal  free  from  cavities. 

The  densities  of  the  castings  are,  hence,  much  lov/er  than 
that  of  alloys  given  by  other  authorities,  and  for  this  reason 
the  density  of  No.  6  A  (87.15  copper,  12.69  tin)  in  the  shape 
of  fine  turnings  gave  the  figure  8.943,  and  turnings  of  ingot- 
copper  gave  the  figure  8.874. 

The  strength  and  density  are  in  a  certain  degree  depend- 
ent upon  each  other,  and  the  greater  the  density  of  an  alloy 
of  any  given  composition  the  greater  the  strength.  This  has 
been  shown  in  experiments  on  gun-metal,  which  uniformly 
exhibits  an  increase  of  strength  with  increase  of  density. 

The  casting  of  small  bars,  such  as  have  been  used  in  the 
experiments  described,  is  especially  unfavorable  to  the  pro- 
duction of  metal  of  great  density,  while  in  the  casting  of  guns 
and  other  large  masses  the  pressure  of  molten  metal  is  much 
greater,  and  all  conditions  favor  the  increase  of  density  and 
of  strength. 

It  is  probable  that  the  actual  specific  gravities  of  all  alloys 
containing  less  than  25  per  cent,  tin  do  not  greatly  vary  from 


356  MATERIALS  OF  ENGINEERING— N OX-FERROUS  METALS. 

8.95,  and  that  the  specific  gravities  of  castings  of  these  alloys 
will  be  less  than  8.95  as  they  exhibit  porosity.  The  specific 
gravity  of  an  alloy  is  increased  by  repeated  working. 

In  determining  the  specific  gravities,  the  pieces  were  first 
washed  in  alcohol  to  free  them  from  any  dirt  or  grease  which 
might  be  attached  to  them,  and  then  thoroughly  dried. 
Before  weighing  in  water,  the  pieces  were  boiled  for  two  or 
three  hours,  to  remove,  as  far  as  possible,  the  air  inclosed  in 
the  pores  of  the  metal,  and  after  cooling  in  the  dish  in  which 
they  were  boiled,  they  were  placed  under  the  receiver  of  an 
air-pump,  and  the  air  was  further  exhausted.  They  were 
then  quickly  transferred  to  distilled  water,  in  which  they  were 
weighed,  suspended  by  a  loop  of  fine  platinum  wire  from 
the  arm  of  the  balance.  The  water  in  which  they  were 
weighed  was  kept  at  the  same  level,  and  the  proper  correc- 
tion made  for  weight  of  the  platinum  wire. 

The  results  given  are  corrected  for  temperature  of  the 
water,  being  reduced  to  the  standard  of  water  of  maximum 
density  (39°.4  Fahr.,  4°.!  cent.). 

If  the  formation  of  the  gas  which  causes  blow-holes  can 
be  prevented,  or  if  it  can  be  removed  from  the  metal  while 
the  latter  is  still  in  a  fluid  state,  it  is  evident  that  the  cast 
metal  will  be  entirely  free  from  them,  and  a  metal  of  great 
density  and  strength  will  be  obtained. 

No  means  has  yet  been  discovered  by  which  this  desirable 
result  may  completely  be  accomplished,  but  it  is  not  improb- 
able that  it  may  be  done  by  treatment  of  the  fluid  metal,  or 
by  the  use  of  fluxes.  The  subject  offers  a  fruitful  field  for 
experiment,  one  which  it  was  proposed  to  explore,  after  con- 
cluding the  researches  on  copper-tin,  copper-zinc,  and  triple 
alloys,  but  one  which  was  not  carried  out  by  the  U.  S.  Board. 

The  specific  gravity  of  an  alloy  is  increased  by  repeated 
tempering  and  rolling. 

The  specific  gravity  of  pure  copper,  according  to  authori- 
ties quoted  in  "Constants  of  Nature"  varies  from  8.360  to 
8.958,  electrolytic,  hammered,  rolled,  or  pressed  copper  giv- 
ing the  highest  figures  and  those  which  are  probably  the  most 
nearly  correct. 


STRENGTH  OF  BRONZES. 


357 


358  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

The  specific  gravity  of  all  alloys  containing  between  25  and 
38  per  cent,  tin,  which  alloys  are  compact  and  homogeneous, 
is  greater  than  8.9  (reaching  8.97  at  the  latter  percentage). 

The  specific  gravities  given  in  the  tables,  as  determined 
from  the  castings,  show  the  cause  of  imperfections  in  strength 
and  other  qualities,  and  indicate  that  one  proper  method  of 
improving  strength  is  to  increase  density.  They  indicate  that 
the  lower  the  specific  gravity  of  alloys  which  show  a  certain 
definite  strength,  the  greater  increase  may  probably  be  ex- 
pected from  any  cause  which  brings  the  specific  gravity  up 
to  8.95. 

Rolling,  hammering,  or  compressing  porous  and  ductile 
metals  increases  density.  Casting  under  pressure  has  the 
same  effect.  It  is  probable  also  that  temperature  of  pouring 
and  rate  of  cooling  have  an  influence  upon  density,  and  the 
use  of  fluxes  which  may  remove  occluded  gases  from  the 
molten  metals  will  increase  it  also. 

The  maximum  density  of  the  series  is  given  by  alloy  No. 
12  (62.31  copper,  37.35  tin,  by  analysis),  the  original  mixture 
of  which  corresponds  to  the  formula  SnCus,  and  is  nearly  ap- 
proached by  alloy  No.  38  (62.42  copper,  37.48  tin).  The  fig- 
ures are  8.970  and  8.956  respectively.  The  former  is  higher 
than  is  given  by  any  authority  known  to  the  Author  for  any 
alloy  of  copp.er  and  tin. 

From  alloy  No.  12  to  the  end  of  the  series,  to  pure  tin,  an 
almost  perfectly  regular  decrease  of  specific  gravity  occurs, 
that  of  tin  being  7.29.  From  the  regularity  of  this  decrease 
of  specific  gravity  it  would  seem  that  these  alloys  are  but 
little  subject  to  porosity  in  castings.  In  these  alloys  the 
density  has  no  definite  relation  to  strength. 

213.  Apparent  Limit  of  Elasticity. — The  apparent  limit 
of  elasticity  has  been  defined  as  the  point  at  which  distortion 
begins  to  increase  in  a  greater  ratio  than  the  force  which 
causes  that  distortion.  In  the  curves  of  deflections  and  elonga- 
tions, and  in  the  autographic  diagrams  of  torsional  stress,  it 
is  the  point  at  which  the  curve  begins  (usually  suddenly)  to 
change  its  direction  and  to  deflect  toward  the  horizontal. 

The  figure  giving  curves  in  which  comparison  is  made  of 


STRENGTH  OF  BRONZES.  359 

the  transverse,  torsional,  and  tensile  resistance,  also  contains 
curves  showing  the  limit  of  elasticity  under  each  of  the  three 
kinds  of  tests.  In  the  general  summary  of  results  (Table  LXV.) 
the  elastic  limits  are  represented  by  parts  of  the  total  re- 
sistance. 

It  will  be  seen  that  the  curves  of  limits  of  elasticity  ob- 
tained from  the  three  kinds  of  tests,  coincide  with  the  curves 
of  resistance  in  the  middle  portion  of  the  series,  that  contain- 
ing the  brittle  alloys,  and  fall  beneath  them  at  the  ends,  the 
figures  in  the  summary  showing  the  elastic  limit  to  be  there 
100  per  cent,  of  the  total  strength,  and  that  of  the  more 
ductile  alloys  to  be  in  some  cases  as  small  as  20  per  cent,  of 
the  total  strength,  and  to  increase  with  the  decrease  of.  ductility. 

In  general,  the  ratio  obtained  by  tensile  test  is  higher 
than  that  obtained  by  either  transverse  or  torsional  test. 

In  the  stronger  alloys,  the  elastic  limit  under  tensile  stress 
is  reached  at  from  50  to  68  per  cent,  of  the  breaking  load,  and 
under  transverse  and  torsional  stress  at  35  to  45  per  cent.  As 
the  percentage  of  tin  is  increased  beyond  17.5  per  cent.,  the 
ratio  of  elastic  limit  to  ultimate  strength  is  increased  ;  alloy 
No.  8  (76.64  copper,  23.24  tin)  giving  a  ratio  of  100  per  cent. ; 
the  elastic  limit  was  not  reached  till  fracture  took  place.  The 
same  result  is  given  by  all  alloys  from  No.  8  to  No.  21  (38.37 
copper,  61.32  tin).  From  No.  21  to  pure  tin,  this  elastic  limit 
is  reached  before  fracture,  by  both  transverse  and  torsional 
tests.  In  both  tensile  tests  of  alloys  containing  between  62.5 
and  82.5  per  cent,  of  tin  the  elastic  limit  was  either  not 
reached  or  only  just  reached  before  fracture  took  place.  In 
these  alloys,  the  ratios  of  elastic  limit  to  ultimate  strength 
appear  much  higher  in  torsional  than  transverse  stress.  The 
ductile  alloys,  containing  large  percentages  of  tin,  give  ratios 
under  torsional  stress  which  gradually  decrease  as  the  per- 
cerftage  of  tin  increases,  the  decrease  being  nearly  regular 
from  98.5  per  cent,  to  45.3  per  cent.,  between  the  alloy  of 
27.5  copper,  72.5  tin,  and  pure  tin.  In  transverse  test,  the 
ratio  is  much  more  nearly  constant,  varying  somewhat 
irregularly  between  the  same  compositions  from  43.8  to  27.3 
per  cent. 


360   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 


STRENGTH  OF  BRONZES.  361 

214.  Moduli  of  Elasticity. — The  moduli  of  elasticity  were 
calculated  from  deflections  observed  in  transverse  test.     The 
figures  given  are  considered  to  be  the  most  probable  moduli 
of  each  bar  within  the  elastic  limit  where  the  deflections  arc 
proportional  to  the  applied  loads.     The  figures  and  the  curve 
show   irregularity,  but  not  greater  than  should  be  expected 
from  metals  of  different  compositions. 

In  alloys  containing  less  than  24  per  cent,  of  tin  (all  the 
stronger  and  more  valuable  alloys)  the  modulus  of  elasticity 
by  transverse  stress  is  about  14,000,000  (984,200  kilogs.  per 
sq.  cm.). 

From  25  per  cent,  to  35  per  cent,  tin,  the  modulus  is  some- 
what greater.  From  35  to  75  per  cent,  there  is  a  very  great 
irregularity,  corresponding  to  the  irregularity  in  strength  and 
other  properties  as  shown  by  test,  and  much  greater  than  any 
other  property. 

From  alloys  containing  70  per  cent,  tin,  to  pure  tin,  the 
moduli  become  a  little  more  regular,  the  tendency  being  to 
decrease  as  the  tin  increases.  The  modulus  of  these  alloys 
averages  a  little  more  than  half  that  of  the  stronger  alloys  con- 
taining less  than  20  per  cent,  of  tin. 

215.  Ductility    is   exhibited  on  the   next   set  of   curves. 
Figure  14.     The  copper-tin  alloys  are  ductile  in  all  directions 
when  they  contain  principally  tin  or  are  nearly  all  copper, 
As  the  proportions  alter  and  become  more  nearly  equal,  the 
ductility  decreases,  as  the  range  between  25  and  75  per  cent, 
tin  is  approached  from  either  side,  and  within  that  range  are 
very  brittle.     The   alloys  rich  in  copper  are  strong,  though 
ductile,  while   those   rich  in  tin  partake  of  the  properties  of 
that  metal.     The  method  of  variation  of  ductility  is  the  same 
for  all  methods  of  test,  but  the  test  by  transverse  loading  of 
bars  gives  greater  opportunity  for  nice  measurement  and  ex- 
hibits better  the  gradual  introduction  of  this  element  as  the 
lessening  percentage  of  tin  passes  the  figure   35   (copper,  65). 
Alloys  containing  less  than  20  per  cent,  tin  or  more  than  85 
per  cent,  gain  in  ductility  rapidly  as  change  of  composition 
goes  on. 

Ductility  is  thus  variable,  quite  smoothly  and  regularly 


MATERIALS  OF  ENGINEERING— NON-FERROUS  METAL& 


STRENGTH  OF  BRONZES.  363 

with  the  composition  of  the  alloy.  In  tension,  ductility  was 
measured  directly,  except  in  the  case  of  the  most  brittle  alloys, 
where  it  was  too  small  to  be  measured.  In  transverse  tests 
it  was  easy  to  obtain  its  measure  by  noting  the  deflection, 
which,  in  some  cases,  was  greater  than  can  be  shown  on  the 
scale  ;  some  bars,  In  fact,  could  not  be  broken  by  bending 
under  the  load.  The  autographic  strain-diagram  probably 
gives  the  best  means  of  comparison.  The  maximum  angle  of 
torsion  is  556.75  degrees,  corresponding  to  an  extension  of 
the  most  extended  fibre,  originally  parallel  to  the  axis,  of  2.2, 
nearly;  the  minimum,  0.4  degree,  corresponds  to  an  extension 
of  but  0.000.006 ;  pure  tin  gives  a  value  200,000  times  greater 
than  the  most  brittle  alloy.  Bars  containing  less  than  12.5 
per  cent,  tin  did  not  break  by  bending  to  a  deflection  of  16 
per  cent,  their  length  and  3j4  times  their  depth.  The  illus- 
trations given  in  the  frontispiece  exhibit  the  fracture  of  a 
number  of  these  alloys,  and  present  to  the  eye  the  characteris- 
tics of  each,  showing  well  the  ductility  or  the  brittleness,  the 
toughness  or  the  crystalline  or  granular  surfaces  revealed  by 
breaking  them. 

216.  Conductivity  for  heat  and  electricity  varies  in  the 
copper-tin  alloys  as  seen  in  Figure  15,  which  represents  the 
data  furnished  by  Calvert  and  Johnson,  and  by  Matthiessen. 
There  is  seen  to  be  a  general  correspondence,  with  a  sudden 
break  at  the  composition,  copper  60  to  70,  which  appears  in 
the  curve  for  heat-conductivity,  but  not  in  that  for  electric 
conductivity.    In  both  cases,  this  property  remains  practically 
constant  for  all  alloys  between  copper  o  and  copper  60,  and 
rapidly  improves  as  the  alloy  becomes  more  nearly  pure  cop- 
per.    The  standard  taken  for  comparison  is  pure  silver.     The 
curves  well  illustrate   the  importance  of  securing  purity  in 
copper  intended  to  be  used  as  a  conductor. 

217.  The  other  Physical  Properties  of  the  copper-tin 
alloys,  as  determined  by  various  authorities,  are  exhibited  in 
Figure  16.     Mallet  gives  data  relating  to  ductility,  mallea- 
bility, hardness,  and  fusibility,  on  which  are  based  several  of 
these  curves.     With  this  curve  of  hardness  is  compared  that 
of  Calvert  and  Johnson,  which  corresponds,  roughly,  with  it 


MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS 


STRENGTH  OF  BRONZES.  365 

so  far  as  it  goes.  Hardness  is  here  seen  to  increase  steadily 
from  pure  copper  to  copper  75,  at  which  point  that  of  mini- 
mum ductility  is  reached.  From  this  point  it  decreases  stead- 
ily and  with  tolerable  uniformity  to  the  opposite  end  of  the 
series. 

Malleability  takes  an  almost  precisely  opposite  course, 
falling  to  zero  at  copper  60-65  and  rising  again  to  the  end 
(pure  tin). 

Fusibility  constantly  lessens,  as  tin  is  added  to  copper, 
from  end  to  end  of  the  whole  range. 

The  curve  of  ductility  closely  follows  that  of  malleability 
in  alloys  rich  in  copper,  but  the  lack  of  cohesion  of  tin  causes 
a  great  falling  off  at  the  opposite  end  of  the  line* 


CHAPTER   X. 

STRENGTH   OF  BRASSES   AND   OTHER    COPPER-ZINC   ALLOYS. 

218.  The  Brasses  include  all  the  copper-zinc  alloys  con- 
taining one-half  copper  and  upwards,  and  a  few  special  alloys 
are  also  given  the  name,  as  are  copper-tin-zinc  alloys,  of  which 
the  tin  forms  but  a  small  proportion.  The  name  bronze  has 
been  applied,  occasionally,  to  these  ternary  alloys,  also.  The 
terms  bronze  and  brass  are  used  indifferently  by  the  older 
writers,  but  the  tendency  to  restrict  each  term  to  a  binary 
alloy,  or  to  a  ternary  alloy  in  which  one  constituent  exists  in 
very  small  proportion,  is  decidedly  observable  among  later 
writers  and  they  will  be  so  used  in  this  treatise. 

In  the  cases  of  the  brasses,  as  in  that  of  the  bronzes,  no 
systematic  investigation  of  the  properties  useful  to  the  engi- 
neer had  been  made  except  by  the  U.  S.  Government.  The 
U.  S.  Board,  to  which  allusion  has  been  already  frequently 
made,  authorized  a  determination  of  "  the  mechanical  proper- 
ties and  of  the  physical  and  chemical  relations  of  alloys  of 
copper,  tin,  and  zinc,"  under  the  arrangement  of  committees 
approved  by  the  Board,  which  assigned  to  the  Committee  on 
Alloys  the  duty  of  "  assuming  charge  of  a  series  of  experi- 
ments on  the  characteristics  of  alloys  and  an  investigation  of 
the  laws  of  combination." 

This  research  was  conducted  in  the  Mechanical  Labora- 
tory of  the  Department  of  Engineering  of  the  Stevens  Insti- 
tute of  Technology  under  the  direction  of  the  Author.  The 
facts  and  data  thus  discovered  and  placed  on  record  *  will  be 
summarized  in  this  chapter  after  reference  to  earlier  work 
on  nearly  related  alloys. 

*  Report  of  U.  S.  Board,   Vol.   II. ;  Ex.    Doc.    23  ;  46th  Congress,  2nd  Ses- 
sion.    Washington  :  Government  Printing  Office,  1881. 


STRENGTH  OF  BRASSES. 


367 


219.  Earlier  Experiments. — Mallet  *  found  the  tenacity  of 
an  alloy  of  copper,  90.7,  zinc,  9.3,  to  be  27,000  pounds  to  the 
square  inch  (1,456  kilogs.  per  sq.  cm.),  with  a  specific  gravity 
of  8.6 ;  with  3  per  cent,  more  zinc  the  strength  was  increased 
to  very  nearly  30,000  pounds  (2,109  kilogs.).  Copper,  85.4, 
zinc,  14.6,  had  a  tenacity  of  about  32,000  pounds  (2,249.6  kilogs.), 
and  with  copper,  83,  zinc,  17,  the  figure  became  31,000  (2,179 
kilogs.).  The  tenacities  varied  little  throughout  the  range 
and  down  to  copper,  2,  zinc,  I,  which  is  a  Muntz  metal'.  Equal 
parts  copper  and  zinc  exhibited  a  tenacity  of  20,000  pounds 
per  square  inch  (1,406  kilogs.  per  sq.  cm.)  in  Mallet's  experi- 
ments;  the  Author  has  obtained,  in  some  cases,  40,000(2,812 
kilogs.).  Alloys  rapidly  become  weaker,  passing  this  maxi- 
mum, as  the  proportion  of  zinc  is  increased,  as  will  be  seen 
later,  passing,  however,  a  second  maximum  at  about  copper, 
10,  zinc,  90,  which  gives  figures  one-third  as  great  as  the  first 
maximum. 

Brass  cartridge  metal  tested  with  copper  and  steel  by  Lt. 
Metcalfe  at  the  Bridesburg  Arsenal  in  samples  trimmed  out 
to  a  contracted  section  of  one  inch  (2.54  cm.), '  minimum 
breadth,  and  0.03  inch  (0.076  cm.)  thick  gave  results  as  fol- 
lows: 


TABLE    LXVI. 

TENACITY  AND  ELONGATION  OF  CARTRIDGE  METAL. 


LOAD. 

PURE 
COPPER. 

COMMERCIAL  COPPER. 

BRASS. 

OPEN    HEARTH 
STEEL. 

Lbs. 

Kilogs. 

Unannealed. 

Annealed. 

T 

II. 

£! 

600 

BOO 

I.OOO 
1,100 
1,200 

I,3«» 
1,400 

J'|oo 

1,000 

1,700 
i,  800 

227 
272 
363 
454 
499 
544 
590 
635 
680 
726 

$ 

0.021 

0.040 
0.078 
0-155 

0.005 
0.020 
0.063 

o.  156 

0.266 

o.o->5 
0.015 
0.040 
0.087 
0.130 
0.214 
0.290 





0.013 

0.025 
0.042 

0.0*2 
0.085 

0.033 
0.050 
0.075 

0.102 
0.152 
0.266 

CO.  27 

0.057 
0.085 

C.IIO 

0.163 
0.270 

0.050 
0.075 

O.IOO 

0.130 
0.165 

O.22O 
0.350 

0.0225 
O.OJO 
0.0425 
0.060 
0.0775 
0.140 
O;23O 

0.005 
0.0075 
0.013 
0.030 
0.065 
0.126 

O.II7 
0.157 
0.217 
0.322 

*  Phil.  Mag.,  Vol.  21,  1842. 


368  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

As  the  test-pieces  were  of  the  "  grooved  "  form  the  elonga- 
tions serve  for  comparison  of  these  specimens,  but  have  no 
absolute  value. 

220.  Sterro-Metal,  a  brass  which  contains  a  little  tin  and 
iron,  was  tested  by  Baron  de  Rosthorn  at  Vienna,  and  gave 
the  following  results :  * 


TABLE    LXVIL 


TENACITY    OF    STERRO-METAL. 


MATERIAL. 

TENACITY. 

Lbs.  per  sq.  in. 

Kilogs.  per  sq.  cm. 

Sterro-metal  ; 
Gun-bronze  ; 

cast 

60,480 
76,160 
85,120 
40,320 

4,252 
5,354 

5,984 

2,834 

forjzed 

cold-drawn  

cast 

This  alloy  contained  copper,  55.04;  zinc,  42.36  ;  tin,  0.83  ; 
iron,  1.77. 

The  proportion  of  zinc  may  vary  from  38  to  42  per  cent, 
without  appreciably  altering  the  value  of  the  alloy.  Tre 
specific  gravity  of  this  metal  was  8.37  to  8.40  when  forged  or 
wire  drawn;  it  has  great  elasticity,  stretching  0.0017  without 
set,  and  costs  30  to  40  per  cent,  less  than  gun-bronze.  It  has 
been  forged  into  guns,  cold  from  the  casting.  The  strength 
of  sterro-metal  containing  one  per  cent,  and  more  of  tin  will 
be  given  in  the  following  chapter  on  ternary  alloys  of  copper, 
tin  and  zinc. 

221.  The  Moduli  of  Elasticity,  E.,  of  various  alloys  have 
been  found,  as  below,  to  the  nearest  round  numbers : 


Holley  ;   "  Ordnance  a.\\d  Armor,"  p.  424. 


STRENGTH  OF  BRASSES. 
TABLE   LXVIII. 

MODULI    OF   ELASTICITY   OF   BRASSES. 


369 


VALUI 

.  OF  E. 

METAL. 

Lbs.  on  sq. 
in. 

Kilogs.    on 
sq.  cm. 

AUTHORITY. 

REMARKS. 

Brass 

9  ooo  ooo 

632,700 

Tredgold. 

1  1  tin  80  copper  cast. 

12,000,000 

843,600 

Wertheim.       ) 

it 

13  ooo  ooo 

QI-J    QOO 

Bauschinger    C 

Rolled. 

As  will  be  seen,  presently,  the  value  is  very  variable  with 
ordinary  cast  alloys  of  copper  and  zinc,  but  should  be  toler- 
ably uniform  with  rolled  and  drawn  materials. 

222.  Copper-Zinc  Alloys,  including  the  brasses,  were 
studied  by  the  Author,  and  the  investigation  was,  as  al- 
ready stated,  conducted  in  a  similar  manner  to  that  described 
in  the  discussion  of  the  alloys  of  copper  and  tin.* 

The  specimens  were  in  the  form  of  bars,  and  were  cast  in 
an  iron  mould  square  in  section,  and  similar  in  dimensions  to 
that  used  in  making  bronzes.  The  experiments  were  made 
upon  these  bars  as  cast  under  ordinary  conditions  as  before. 
The  effects  of  different  methods  of  casting,  of  slow  and  rapid 
cooling,  of  compression,  either  of  the  fluid  metal  or  after 
solidification,  and  of  rolling,  tempering  and  annealing,  were  to 
have  been  made  the  subject  of  a  special  research. 

Two  series  of  'these  alloys  were  made  and  tested.  The 
first  series  was  composed  of  bars  differing  in  composition  by 
5  per  cent.  The  bars  of  the  second  series  also  differed  in 
composition  by  5  per  cent.,  the  first  bar  containing  2^/2  per 
cent,  zinc,  the  last  bar  containing  97^2  per  cent. 

The  bars  were  first  tested  by  transverse  stress ;  the  two 
pieces  remaining  after  each  transverse  test  were  turned  to 
size  and  tested  by  tension,  and  the  four  pieces  thus  formed 

*  This  account  is  mainly  abridged  from  the  Report  to  the  Committee  on 
Alloys  of  the  U.  S.  Board. 
24 


37O  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

were  tested  by  torsion.  Some  tests  were  made  by  compres- 
sion. The  turnings  from  the  tension  test-pieces  were 
analyzed.  The  specific  gravities  were  also  determined. 

The  total  weight  of  each  casting  was  4.5  kilograms  (9.92 
pounds). 

223.  Compositions  Tested.— A  following  table  (p.  371) 
gives  the  compositions  of  the  bars  according  to  the  original 
mixtures,  the  compositions  of  two  portions  of  each  bar  as 
subsequently  determined  by  analysis,  and  the  specific  gravi- 
ties. 

Bar  No.  16  was  made  by  melting  together  the  upper  half 
of  bar  No.  17  (21.00  copper,  77.59  zinc)  and  the  lower  half  of 
bar  No.  15  (25.98  copper,  72.90  zinc). 

The  mould  was  heated  each  time  before  pouring  into  it  the 
molten  metal,  the  temperature  given  to  it  being  higher  the 
larger  the  amount  of  copper  in  the  alloy.  In  melting  the 
metal  for  bars,  No.  7  to  No.  21  (35  per  cent,  zinc  to  pure  zinc), 
inclusive,  except  No.  16,  the  copper  was  melted  first  and 
covered  with  a  layer  of  charcoal.  The  zinc  was  melted  in  a 
separate  crucible,  and  poured  into  the  crucible  containing  the 
molten  copper,  through  the  layer  of  charcoal.  The  mixture 
was  thoroughly  stirred  with  a  dry  stick.  Some  volatilization 
of  the  zinc  took  place,  the  amount  being  greater  at  some  times 
than  at  others ;  but  the  causes  of  this  variation  were  not 
determined. 

Bars  No.  I  to  No.  6  (5  to  30  per  cent,  zinc)  were  made  by 
first  melting  the  copper,  and  then  adding  the  zinc  in  the  solid 
state.  The  losses  of  zinc  vary  very  irregularly,  and  in  two 
cases,  bars  Nos.  18  and  20(85  and  95  per  cent,  zinc),  there  ap- 
peared to  have  been  a  greater  loss  of  copper  than  of  zinc. 

The  temperature  of  casting  was  then  found  by  the 
formula 


in  which  P  is  the  weight  of  the  water,  P  the  weight  of  metal 
poured,  /  the  temperature  of  the  water  before,  and  t'  after 


STRENGTH  OF  BRASSES. 


37* 


pouring,  and  c  the  specific  heat  of  the  alloy.  The  specific 
heat  was  assumed  to  be  the  mean  of  the  specific  heats  of  the 
components. 

The  following  table  gives  the  temperatures : 

TABLE    LXIX. 

ALLOYS   OF   COPPER    AND    ZINC. 
Estimation  of  Temperatures  of  Casting. 


Composition 
by  original 
mixture. 

Weight 
grammes. 

Temperatures, 
Fahrenheit, 
Degrees. 

Temperatures 
of  casting. 
Degrees. 

Acsumed 

specific 

Remarks. 

i 

1 

u 

jj 

i 

i 

. 

1 

1 

heat. 

ll 

4)  *« 

£ 

U 

N 

5 

rj 

£ 

tb 

« 

U, 

<-> 

i... 

95 

5 

907 

131.8 

54 

"4 

60 

0.09517 

4454 

24567 

Second  casting. 

2.. 

3-- 

e 

10 

'5 

907 
907 

212.3 

321.4 

53 

155 

65 
loo 

0.09519 
0.09521 

3035 
3120 

i667  :  6 

Poured  thick. 

4- 

So 

20 

907 

447-3 

58 

172 

114 

0.09523 

2600 

1426.6 

5-- 

75 

25 

907 

381.26 

54 

100 

o  09525 

2652 

M55  -5 

6.. 

70 

30 

907 

257-9 

52 

120 

68 

0.09527 

2631 

'443-8 

7-- 

65 

35 

907 

259.9 

56 

120 

64 

0.09529 

2464 

1351.2 

8.. 

60 

40 

907 

65 

J52 

0.09531 

2584 

1417.7 

g.. 

55 

45 

907 

182.6 

61 

109 

48 

0-09535 

2610 

ro.. 

50 

50 

907 

199-5 

51 

104 

50 

0.09535 

2492 

1366.5 

ii.. 

45 

55 

907 

237-4 

53 

102 

49 

0-09537 

2065 

1129.7 

12.. 

40 

60 

907 

223.3 

61 

112 

0^9539 

2284 

1251.1 

14.. 

35 
30 

65 
70 

907 
907 

185.9 
203.6 

£ 

102 

no 

45 
50 

0.09541 
0.09543 

2403 
2444 

'317.3 
1340.1 

Second  casting. 

15-- 

25 

75 

907 

168.0 

61 

98 

37 

0.09545 

2191 

i*99-5 

Second  casting. 

16 

Not  taken. 

17.. 

20 

80 

907 

169.3 

51 

.85 

34 

0-09547 

1094 

1089.6 

Second  casting. 

18.. 
19.. 

15 

10 

85 
90 

9"7 
907 

316.0 
289.5 

56 
54 

16 
106 

60 
52 

0.09549 
0.09551 

1812 

'9*3-9 

Second  casting. 

20.. 

5 

95 

907 

163.0 

60 

:73-5 

13-  r 

0-095-3 

860 

460.0 

21.  . 

0 

100 

4535    597-3 

5° 

70 

20 

0.09555 

1660 

904.1 

224.  External  Appearance  of  the  Bars.— The  surfaces  of 
bars  No.  I  to  No.  8  (5  to  40  per  cent,  zinc,  original  mixture) 
had  a  similar  color  and  appearance,  being  generally  of  a  dark 
yellow  color,  inclined  to  copper-red  toward  the  copper  end 
of  the  series,  and  more  or  less  oxidized.  No.  i  (5  per  cent, 
zinc,  original  mixture)  was  variegated  in  color,  exhibiting 
iridescence  in  places,  the  prevailing  tints  bein^  red,  yellow, 
brown,  and  green.  No.  2  (10  per  cent,  zinc)  was  rough,  blow- 
holes, ridges  and  depressions  were  found  over  the  whole  of  the 
bar.  The  others,  from  No.  I  to  No.  7  (5  to  35  per  cent,  zinc), 
were  smooth.  No.  8  (40  per  cent,  zinc)  was  iough,  the  rough- 


372  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

ness  being  caused  by  slight  cavities  or  blow-holes  of  irregular 
shape,  none  of  which  were  deep.  These  bars  were  soft 
enough  to  be  cut  with  a  saw,  the  freshly-cut  surface  varying 
from  yellowish-red  at  No.  I  to  light  yellow  at  No.  5  to  No.  7 
(25  to  35  per  cent,  zinc),  No.  8  (40  per  cent,  zinc)  being  red- 
dish-yellow. The  hardness  gradually  increased  with  the  in- 
crease of  zinc. 

Nos.  9,  10,  and  n  (45  to  55  per  cent,  zinc)  had  surfaces 
similar  in  color  to  the  preceding,  but  darker,  approaching 
brown,  and  in  some  places  covered  by  a  light  gray  scale. 
They  were  harder  than  Nos.  I  to  8,  but  could  be  cut  in  the 
lathe  with  a  good  tool.  It  was  noted  that  Nos.  5,  6,  and  7 
had  a  light  yellow  color,  while  the  bars  on  each  side,  contain- 
ing either  less  or  more  copper,  were  reddish-yellow. 

Nos.  12,  13,  and  14  (60  to  70  per  cent,  zinc)  had  a  yellow- 
ish outside  surface,  a  very  thin  skin  ;  the  metal  itself  when 
broken  was  nearly  white. 

The  yellowish  skin  contained  more  copper  than  the  rest 
of  the  casting ;  it  sometimes  was  so  soft  that  it  could  be  cut 
or  bent,  while  the  inside  of  the  bar  was  nearly  as  hard  as 
glass  ;  this  was  not  determined  by  analysis.  This  soft  yellow 
coating  found  on  white  alloys  of  copper  and  zinc  was  described 
by  Mr.  F.  H.  Storer.*  The  colors  of  the  fractured  surfaces 
of  Nos.  12,  13,  and  14  were  nearly  white.  They  were  too 
hard  to  cut  in  the  lathe.  The  ground  surface  of  No.  12  was 
brownish  yellow.  The  ground  surface  of  No.  13  had  a  yellow 
tint,  that  of  No.  14  was  nearly  silver-white. 

This  sudden  change  between  No.  n  and  No.  12  (from  55 
to  60  per  cent,  of  zinc)  corresponds  to  that  observed  in  the 
copper-tin  alloys  of  24  to  30  per  cent,  of  tin. 

Between  No.  14  and  No.  15  another  change  occurs,  the 
yellow  skin  seen  in  No.  14  being  entirely  wanting  in  No.  15  ; 
the  color  of  the  outside  surface  of  the  latter  is  a  dull  bluish- 
gray.  The  fractured  surface  of  No.  15  is  bluish-gray,  but 
lighter  than  the  outside.  No.  15  is  much  softer  than  No.  14, 
and  can  be  cut  in  the  lathe,  although  with  difficulty. 

"  Memoirs  of  the  American  Academy,"  vol.  viii.,  1860,  p.  54. 


STRENGTH  OF  BRASSES.  3/3 

From  No.  15  to  No.  20  (75  to  95  per  cent,  zinc)  the  sur- 
faces are  much  alike,  bluish-gray  and  nearly  smooth,  the 
color  becoming  lighter  as  the  proportion  of  zinc  increases. 
Hardness  decreases  with  increase  of  zinc.  No.  21,  all  zinc,  is' 
softer  than  No.  20,  and  lighter  in  color.  The  fractured  and 
freshly  cut  surfaces  of  all  bars  from  No.  15  to  No.  21  are 
bluish-gray.  No.  20  and  No.  21  only  show  a  crystalline  ap- 
pearance, the  others  were  finely  granular. 

We  may  divide  the  alloys  of  copper  and  zinc  into  three 
classes,  each  of  which  has  a  distinct  color.  The  first  class 
includes  those  containing  less  than  55  per  cent,  of  zinc,  and 
may  be  called  the  yellow  class.  These  are  also  the  useful 
metals.  The  second  class  includes  those  containing  between 
60  and  70  per  cent,  of  zinc,  which  are  nearly  silver  white  and 
exceedingly  brilliant  and  hard  and  brittle.  These  have  a 
yellow  skin.  The  third  class  includes  all  those  having  more 
than  75  per  cent,  of  zinc,  and  are  bluish-gray,  much  softer  as 
well  as  stronger  than  the  second  class. 

The  alloys  containing  between  55  and  60  per  cent,  zinc 
and  those  containing  between  70  and  75  per  cent,  zinc,  show 
regular  gradations  between  the  first  and  second,  and  second 
and  third  classes,  respectively,  the  changes  from  one  class  to 
the  other  taking  place  gradually,  but  within  narrow  limits. 

225.  Fractures;  Colors. — The  fractures  of  these  alloys 
were  examined  by  Prof.  A.  R.  Leeds,  who  furnished  the  fol- 
lowing description  of  their  color  and  structure  : 

No.  o  (cast  copper). — Coarsely  fibrous,  and  radiate  from 
centre  of  surface  of  fracture.  Color,  dark  red  from  superficial 
oxidation.  Fibres,  interrupted  and  dotted  over  with  minute 
ridges  with  sharp  lines  of  separation. 

No.  I  (96.07  copper,  3.79  zinc). — Surface,  confusedly  vesic- 
ular and  projecting  between  the  vesicular  cavities  upward 
into  sharp  points.  Color  of  centre,  brilliant  yellow-red,  chang- 
ing to  light  red  on  sides  of  fracture.  The  latter  portion  was 
likewise  radiate  in  character,  approaching  No.  o. 

No.  2  (90.56  copper,  9.42  zinc). — Fracture,  closely  resemb- 
lirg  No.  I,  with  vesicular  surfaces  inferior  in  size.  Color, 
more  nearly  approaching  yellow. 


374  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

No.  3  (89.80  copper,  10.06  zinc). — Fracture,  highly  vesic- 
ular and  extremely- jagged  from  the  great  number  of  minute 
projecting  points.  Light  yellow  in  centre,  and  feebly  reddish- 
yellow  at  sides  of  fracture.  The  latter  portion  was  likewise 
radiate  in  character. 

No.  4  (81.91  copper,  17.99  zmc). — Surface  in  character  re- 
sembling No.  3,  but  less  acutely  jagged.  Color,  brass-yellow. 

No.  5  (76.65  copper,  23.08  zinc). — Surface  pitted  over  with 
minute  rounded  depressions,  and  ridged  up  into  regular  ele- 
vations, with  a  somewhat  rough  feeling  to  the  touch.  Color, 
full  yellow. 

No.  6  (71.20  copper,  28.54  zinc). — Resembling  No.  5,  but 
the  elevations  more  prominent  and  more  acute  to  the  sense 
of  touch.  Color,  dark  yellow. 

No.  7  (66.27  copper,  33.50  zinc). — Centre  of  surface  of 
fracture  largely  vesicular,  the  surfaces  of  the  vesicles  being 
likewise  covered  with  minute  rounded  depressions.  Color, 
gold-yellow. 

No.  8  (60.90  copper,  38.65  zinc). — Surface  slightly  rough 
and  uneven,  with  a  few  smooth,  rounded  cavities.  Color, 
somewhat  orange-yellow,  apparently  having  undergone  a 
slight  superficial  oxidation. 

No.  9  (55.15  copper,  44.44  zinc). — Extremely  rough  and 
uneven.  Surface  tarnished,  of  dull  reddish-yellow  color. 
One  large  rounded  cavity  coated  with  smooth  surface  of  gold- 
yellow  color. 

No.  10(49.66  copper,  50.14  zinc). — Confusedly  vesicular, 
with  regular  surface  of  demarkation  between  the  depressions. 
Not  homogeneous.  Surface  at  centre,  deep  yellow,  surrounded 
by  the  larger  portion  of  a  whitish-yellow  alternating  with 
reddish-yellow,  and  bounded  at  sides  by  a  radiated  border  of 
a  similar  color.  Splendent. 

No.  ii  (47.56  copper,  52.28  zinc). — In  character  somewhat 
approaching  No.  10,  but  the  lines  of  demarkation  between 
depressions  less  evident,  and  the  projecting  ridges  less  promi- 
nent. Color,  reddish-white.  Brilliant. 

No.  12  (41.30  copper,  58.12  zinc). — Largely  conchoidal 
surface  of  fracture,  with  few  surfaces  and  those  smooth. 


STRENGTH  OF  BRASSES.  375 

Dull  orange-yellow  color.  Splendent.  (The  color  of  this 
fracture  was  nearly  silver-white  when  freshly  broken,  but 
changed  to  yellow  by  oxidation.) 

No.  13  (36.62  copper,  62.78  zinc). — Character  of  surface 
same  as  No.  12.  Color  more  silvery.  Splendent. 

No.  14  (32.94  copper,  66.23  zinc). — Conchoidal  fracture, 
with  surface  covered  with  rounded  depressions  too  minute  to 
be  separately  visible  to  the  naked  eye.  Color,  bluish-white. 
Splendent. 

No.  15  (25.77  copper,  73.45  zinc). — Minutely  vesicular 
fracture,  giving  a  slightly  rough  surface.  Color,  dull  bluish- 
white. 

No.  17  (20.81  copper,  77.63  zinc).— Similar  in  color  and 
surface  to  No.  15,  but  radiate  fibrous  in  structure. 

No.  1 8  (14^19  copper,  85.10  zinc). — Closely  resembling  No. 
17.  Color,  dull  bluish-white. 

No.  19  (10.30  copper,  88.88  zinc). — Surface  in  small,  un- 
even ridges,  dotted  over  with  rounded  depressions  of  brilliant 
silvery  surface.  General  color  of  mass,  dull  bluish-white. 

No.  20  (4.35  copper,  94.59  zinc). — Extremely  jagged  sur- 
face. Large  vesicular  depressions,  with  splendent  silvery 
surface.  Color  of  mass,  bright  bluish-white.  Sides  of  fract- 
ure, crystalline  radiate. 

.No.  21  (cast  zinc). — Large  lamellar  crystalline  plates,  with 
rough  surfaces  of  fracture  between  the  laminae.  Structure  of 
crystals  also  radiating  from  centre.  Splendent.  Bluish- 
white. 

The  second  series  comprises  twenty  bars.  They  were 
tested,  mixed,  and  cast  in  the  same  manner  as  those  of  the 
first  series.  The  table  (p.  378)  gives  the  composition  mixture 
of  each  bar,  the  composition  by  analysis,  and  specific  gravity. 

226.  Temperatures  of  Casting.  —  The  following  table 
contains  the  temperatures  of  casting  : 


3/6  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

TABLE  LXX. 


ALLOYS  OF  COPPER  AND   ZINC. 
Temperatures  of  Casting. 


H 

TEMPERA— 

COMPOSITION 
BV  ORIGINAL 
MIXTURE. 

WEIGHTS, 
GRAMS. 

TEMPERATURES. 

FAHRENHEIT. 
(DEGREES.) 

X 
y 

E 

TURES    OF 
CASTING. 

(DEGREES.) 

-    1 

i 

^ 

u 

REMARKS. 

U 

•          '          O 

C              ctf 
N             ^ 

| 

"rt 

'3 

J 

1 

ASSUMED  S 

Fahrenhei 

Centigrad 

Temperature  not  taken. 

ii 

7-5 

907 

167.26 

64 

112 

48 

0.09518 

2847.2 

1564- 

Temperature  not  taken. 

s'l 

z7-5 

907 

277.17 

64 

I40 

76 

0.09522 

2752.3 

1511.3 

77-5 

22.5 

907 

482.59 

68 

1  88 

120 

0.09524 

2558.7 

1403-7 

72-5 

27.5 
32.5 

907 
907 

426.95 
577-7° 

60 

64 

158 
1  80 

98 

ir6 

0.09526 
0.09528 

2343-9 
2091  .8 

1284.4 
IJ44-3 

62!s 

37-5 

907 

439-55 

63 

1  58 

I05 

0.09530 

2411.911338.8 

57-5 

42.5 

907 

397-42 

53 

158 

100 

0.09532 

2552-7 

1400.4 

52.5 

47-5 

907 

339-05 

60 

142 

82 

0-09534 

2444.3 

1339-5 

47-5 
42-5 
37-5 
37-5 

52.5 
57-5 
62.5 
67.5 

907 

907 
907 
907 

296-53 
388.15 

327.33 
224.45 

U 

64 
83 

130 
158 
142 
138 

76 
90 
78 
50 

0.09536 
0.09538 
0.09540 
0.09542 

2568.2 
2363-3 
2407-9 
2255.8 

1409. 
1295-1 

I235.4 

Mixed  well;  poured  hot. 
Considerable  zinc  vola- 

tilized ;  poured  thick. 

27-5 

72-5 

907 

221.19 

66 

112 

46 

0.09544 

2088.7 

1142.6 

22.5 

77.5 

907 

322.52 

62 

125 

63 

0.09546 

1981-3 

1082.9 

T7-5 

82.5 

907 

278.40 

59 

I04 

45 

o.c9548 

1639-7 

893.1 

I2-5 

87.5 

907 

165.18 

68 

95 

27 

0.09550 

1647.7 

897.6 

7-5 

92.5 

907 

197.87 

55 

92 

37 

0.09552 

1867.9 

1019.9 

2.5 

97.5 

907 

180.36 

67 

93 

26 

0.09554 

1461.8 

794-3 

The  cast-iron  mould  was  heated  before  pouring  bars  Nos. 
31  to  41  inclusive,  but  was  cold  for  bars  Nos.  21  to  30  inclu- 
sive ;  when  the  molten  metal  had  a  high  enough  temperature 
given  it,  no  difficulty  was  experienced  by  chilling. 

As  will  be  seen  later,  the  zinc  used  in  the  second  series, 
although  sold  as  of  good  commercial  purity,  contained  one 
per  cent.  lead. 

227.  Analyses. — The  following  table  gives,  at  one  view, 
all  the  quantities  thus  far  referred  to : 


STRENGTH  OF  BRASSES. 


377 


TABLE  LXXI. 

ALLOYS  OF   COPPER  AND   ZINC. 

Analyses  and  Specific  Gravities. 
First  Series. 


ORIGINAL 
MIXTURE. 

ANALYSES. 

VARIATION   OF 
COMPOSITION. 

MEAN 
.     ANALYSES. 

«-• 

E  > 

3 

\\ 

9 

b 

13 

S. 

K 

o 
B 

*| 

| 

1 

jj 

N 

U 

i 

N 

| 

N 

! 

N 

u 

i 

i 

i  A.... 
i  B.... 

2    A.... 
2    B.... 

95 
95 
90 
9° 

5 
5 

10 
IO 

95.98 
96.16 
90.49 
90.62 

3.90 

3  68 
9.48 
9.35 

+  0.98 

+  1.16 
+  0.49 
+  0.62 

—  1.  10 

-1.32 
-0.52 

-0.65 

[96.07 

3-79 
9.42 

(  8.854 
j  8.758 
18.788 

[3.825 
[8.773 

3  A.... 

IB:::: 

4  A.... 
4  B.... 
5  A.... 
5  B.... 

1 

80 
75 
75 

15 
15 

20 
20 
25 
25 

89.31 
90.29 
81.97 
81.85 
77.84 
75-45 

10.54 
7-57 
17.95 
18.03 
21.78 
24-37 

+  4.3: 
+  5-29 
+  i  97 
+  185 
+  2.84 
+  o  45 

-4.69 
-5-43 
—  2.05 
-1.97 

—0.63 

sg.bo 
[81.91 
[76.65 

10.  06 

17-99 
23.08 

j  8.643 
1  8.669 

i  8.603 

1  8.593 
j  8.539 
(8.517 

[3.598 
[3.528 

6  A.... 
6  B.... 

/o 
70 

3° 
30 

71.34 
71  .06 

28.55 
28.52 

+  i  34 

IJ;J| 

71.20 

28.54 

1  8.458 
1  8.429 

}  8.444 

7  A  ... 
7  B.... 
8  A.... 
8  B.... 

65 

60 

55 
55 

35 
35 
40 

4° 
45 
45 

67.24 
65.29 
62.68 
59-19 
59.13 
51.16 

32-49 
34-51 
36.91 
40.39 
4036 
48.52 

+  2.24 
+  0.29 
+  2.68 
-0.81 
+  4.13 
-3-84 

-2.51 
-0.49 
-3-09 
+0.39 
-4.64 
+3-52 

;  66.27 
60.94 

•55  *5 

33.50 

38.65 
44-44 

i  8.392 
1  8.350 
j  8.443 
18-367 
j  8.369 
18.io6 

[8.371 
}  8.405 
[8.283 

10  A  
10  B  

50 
50 

50 

5° 

52.21 
47-" 

47-48 
52.79 

+  2.21 
-2.89 

-2.52 

+  2.79 

j  49.66 

50.14 

(8.301 
1  8.281 

8.291 

ii  A  
ii  B.... 

12    A    ... 
12    B.... 

45 
45 
40 
40 

55 

i! 

60 

47-45 
47.67 
42.09 
40.51 

52.35 
52.20 
57-32 
58.91 

+  2.43 
+  2.67 

+  2.09 

+0.51 

-2.65 
-2.80 
-2.68 
-1.09 

[47-56 
[•41.30 

52.28 
58.12 

8'.c6i 
'  8.061 

8.061 

i^  A.... 
13  B.... 

35 
35 

65 

65 

36.52 
36.72 

63.20 
62.36 

+  1.52 
+  '..72 

-i.  80 
-2.64 

36.62 

62.78 

7.988 
7-959 

!7-974 

14  A.... 

SB:::: 

30 
30 

70 
70 

34-71 

67.84 
64.62 

+  1.17 
+4.71 

-2.16 
-5-38 

•32.94 

66.23 

.  7.847 
7-775 

7.811 

15  A.... 
15  B.... 
16  A.... 
16  B.... 

25 
25 
22.5 
22.5 

75 
75 
77-5 
77-5 

25-56 
25.98 
26.44 
25.40 

74.00 
72.90 
72.73 
73.38 

+  0.56 
+0.08 
+  3-94 
+  2.90 

-  I.OO 
—  2.10 

-4-77 
-4.12 

25.77 
[25-92 

73-45 

J  7-627 
1  7-722 
J7.694 
l7-684 

[/•C87 

17  A.... 
17  B.... 

20 
20 

80 
80 

21.00 
20.  6l 

77-59 

+  1.00 

+  0.61 

-2.41 
—2.33 

[20.81 

77.63 

j  7-500 
1  7.336 

[7.4^8 

18  A.... 
18  B.... 

15 

15 

If 

13.86 
14.51 

86!  03 
84.16 

-1.14 
-o.49 

+  1.03 
-0.84 

[14.19 

85.10 

(7.166 
1  7.159 

[7-163 

19  A.... 
19  B.... 

XO 

xo 

oo 
oo 

10.41 
XO.X9 

89.02 
88.74 

+  0.41 
+  0.19 

—0.98 
—  1.26 

[10.30 

88.88 

j  7.181 
(  7.325 

[7.253 

20   A.... 
20    B.... 

5 
5 

95 
95 

4-36 

94.69 
94.48 

-0.67 
-0.64 

-0.31 
—0.52 

[,.35 

94-59 

j  7-177 
1  7.038 

[7.108 

21    A 

o 

IOO 

7.140 

J 

21    B.... 

o 

100 

/     *V£ 

(7-143 

MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS 

TABLE    LXXL— Continued. 
Second  Series. 


ORIGINAL 
MIXTURE. 

ANALYSES. 

VARIATION  OF 
COMPOSITION. 

MEAN   ANALYSES. 

g 

Z 
u  > 

K 

0 

K   H 

i 

c 

jj 

U 

U 

L) 

z 

i° 

i 

a 

u 

.0 

a 

g 

rt 

a 

C 

a 

1 

! 

U 

w 

W 

&5 

<5 

N 

S 

N 

J 

U 

N 

U 

N 

3: 

22   A.... 
22    B.... 

97-5 

97-5 

2.5 

2.5 

97.98 
97.68 

i.  60 

2^6 

None.* 
None.* 

+0.48 
+  0.18 

—0.90 
-0-34 

[97.83 

1.88 

0       j 

8.786 
8.796 

[  8.791 

23  A  
23  B.... 
24  A.... 
24  B  ... 

92.5 
92.5 
87.5 
87.5 

7-5 
7-5 
12.5 

I2-5 

92.65 
91.99 
88.86 
89.01 

7.42 
7.94 
ii  06 
10.88 

Trace. 
Trace. 

0.12 

0.16 

+  0.15 
—  0.50 
+  1.36 
+  1.51 

—0.08 
+  0.44 
-1.44 
-1.62 

[92.32 
[88.94 

7.68 
10.97 

Trace  j 

0.14-j 

S.724 
8.767 
8.764 
8.729 

[  8.746 

}    8.747 

25  A.... 
25  B  

82.5 
82.5 

17-5 
^•S 

82.  8^ 
83.00 

17.06 
16.90 

0.17 
0.16 

+  0-35 
+  0.50 

~°-44 
—0.60 

[82.93 

16.98 

0.17-j 

8.662 
8.603 

[    8.633 

26  A.... 
26  B.... 
27  A.... 
276.... 

77-5 
77-5 
72-5 
72.5 

22.5 
22.5 

27.5 
27.5 

79-13 
75.65 
75.13 
71.27 

20.77 
24.12 
24.51 
28.42 

0.06 

S3 

0.21 

+  1-63 
-1.85 
+  2.63 
-1.23 

+  1.62 
-2.99 
+  0.92 

[77-39 
[73-20 

22.45 
26.47 

O.IO  J. 

o.ig-j 

8.607 
8.542 
8.511 
8.418 

[    8.574 
[    8.464 

28  A... 
28  B  .... 

67-5 
67-5 

32.5 

32.5 

70.65 
68.82 

29.16 
30.95 

O.ig 
0.23 

+  2>I5 
+  1.32 

-3-34 
-1-55 

[69.74 

30.06 

0.21-j 

8.401 
8.366 

[   8.384 

29  A.... 

2d    B  .  .  .  . 

62.5 
62.5 

37-5 
37-5 

63-36 

36.46 
36.26 

O.IO 
0.12 

+  0.86 

+  1.02 

-  1.04 
-1.24 

[63.44 

36.36 

O.II  j 

8.417 
8.405 

[  8.4- 

30  A.... 
30  B  

57-5 
57-5 

42.5 
42.5 

58.22 
58.75 

4L25 

40.94 

0.47 
0-37 

0.72 
1.25 

-ilsl 

[o8.49 

41.10 

0.42] 

8.367 
8.358 

[      8.363 

31  A.... 
31  B.... 

52.5 
52.5 

47-5 
47-5 

55-02 
54.69 

44-57 
44-99 

0.40 
0-34 

2.52 
2.19 

-2.93 
-2.51 

[54.86 

44.78 

0-37J 

8.322 
8.280 

[      8.301 

32  A.... 
32  B.... 

47-5 
47-5 

52.5 
52.5 

49.05 

48.85 

50.71 
50.93 

0.32 
0.26 

1-55 

-1.79 
-1-57 

[48.95 

50.82 

0.29| 

8.228 
8.203 

[   8.216 

S3  A.::: 

33  B.... 
34  A.... 
34  B  .... 

42.5 
42.5 
37-5 
37-5 

57-5 
57-5 
62.5 
62.5 

43.68 
43-  of 
38.25 
38.46 

55.89 
56.55 
61.18 
60.92 

0.41 

0.3  + 
0.62 

i!i8 

0.54 

0.75 
0.90 

-1.61 

-0.95 
-1.32 
-1.58 

[43.36 
[38.36 

56.22 
61.05 

0.38| 

o.6o-j 

8.068 
8.999 
7.987 
7.976 

[   8.034 
[   7-982 

35  A.... 
35  B.... 

32.5 
32.5 

67- 
67- 

35.52 

63.55 
63.87 

o'.66 
0.66 

+  3-33 
+  3.02 

-3-95 
-3-63 

[35.68 

63  -71 

o.66J 

7-973 
7-959 

[   7.966 

36  A.... 
36  B.... 

27-5 
27.5 

72. 
72. 

28.78)  70.59 
29.62    69.75 

0-55 
0.55 

+  1.28 

+  2.12 

-1.91 
-2-75 

[29.20 

70.17 

0-55) 

7.746 

[   7.766 

37  A.... 
37  B.... 

22.5 

22.5 

77- 
77- 

l\:ll 

77.40 
77.46 

0.70 
0.63 

—0-73 
—0.64 

—  o.  10 
-0.04 

[21.82 

77-43 

0.67} 

7-452 
7-379 

[   7.4i6 

38  A.... 
38  B.... 

17.5)82. 

17.16 
17.81 

81.87 
81.36 

0.99 
0.86 

—0.34 
+  0.31 

—  0.63 
-1.14 

[i7.49 

81.62 

o.93J 

7-231 
7.218 

[   7-225 

39  A.... 
39  B.... 

12.5(87. 
12.587. 

11-75 
12.48 

87.19 
86.14 

o-99 

1.22 

-0.75 

—  O.O2 

-0.31 
-1.36 

[  12.12 

86.67 

i.n-j 

7-258 
7.217 

j-   7.238 

40  A.... 
40  B.... 

7-5,92. 
7-592- 

7.19 
7.21 

92.34 
91.79 

0-54 

1.02 

-0.31 
—  O.29 

—  0.16 
-0.71 

[     7-20 

92.07 

o.78J 

7-293 
6.968 

[   7-131 

41  A.... 
41  B.... 

2-5  97- 
2-597- 

2.63 
2.26 

96.20 
96.65 

1.  08 
I.  O2 

+  O.T5 
—0.24 

-1.30 
-0.85 

[   2.45 

96.43 

,o5] 

7.177 
6.982 

[   7.080 

I 

228.  Results  of  Tests. — The  next  table  contains  the  data 
obtained  by  test,  arranged  in  order  of  composition,  beginning 
with  copper  and  ending  with  zinc,  and  carefully  classified. 
The  figures  are,  in  each  case,  averages  derived  from  two  or 
more  tests  each. 


*  No.  22  A  had  0.37  per  cent,  iron  and  22  B  0.24  per  cent.  iron, 
others  had  no  iron  or  only  traces. 


The 


s  5 

X 

3  I 

S  8 

n  fc 

<  o 


COMPRES- 
ION TESTS. 


STRENGTH  OF  BRASSES. 
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380 


MATERIALS  OF  ENGINEERING.— NON-FERROUS  METALS. 

I 


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S  TRENG  TH  OF  BRA  SSES.  3  8 1 

229.  Conclusions  from  Tests. — In  the  preceding  table, 
the  "  breaking  load  "  by  transverse  stress  is  that  which  either 
causes  a  deflection  of  3^  inches  (9  cm.),  or  breaks  the  bar 
within  that  limit.  The  limit  of  elasticity  is  not  a  definitely 
marked  point  in  any  cases  in  which  brasses  or  bronzes  are 
under  test,  and  the  quantity  here  given  as  a  limit  is  to  be 
taken  as  approximate  only,  and  not  as  representing  a  fixed 
natural  quantity.  The  moduli  of  elasticity  were  cakulated 
from  a  series  of  deflections  and  loads,  and  the  highest  of  the 
series  of  values  so  obtained  is  usually  recorded  as  probably 
most  correct,  errors  of  observation  and  accidental  errors  usu- 
ally operating  to  depress  the  value. 

Alloys  containing  less  than  10  per  cent,  zinc  were  usually 
somewhat  defective  and  spongy.  Fluxing  may  be  expected 
to  give  sound  casting  only  when  special  care  is  taken,  as  cop- 
per has  a  great  affinity  for  oxygen  and  absorbs  air  freely  when 
the  metal  is  fluid. 

Alloys  containing  less  than  55  per  cent,  zinc  are  yellow, 
and  have  been  classed  as  "  useful  alloys/'  Those  containing 
less  than  40  per  cent,  are  noticeably  weaker  than  those  con- 
taining from  40  to  55.  The  former  are  ductile  and  have 
either  a  fibrous  or  an  earthy  fracture  ;  the  latter  are,  in  some 
cases,  of  nearly  or  quite  double  their  strength,  with  less  duc- 
tility, and  the  fractures  are  granular  and  lustrous.  The  maxi- 
mum strength  is  found  not  far  from  the  composition,  copper, 
60 ;  zinc,  40.  The  white  alloys  (zinc,  40  to  50 ;  copper,  60  to 
50)  are  weak,  brittle,  vitreous,  and  useless  for  ordinary  pur- 
poses of  construction.  The  blue-gray  alloys  (zinc,  70  to  100) 
are  granular  or  crystalline,  stronger  than  the  white,  but  weaker 
than  the  yellow  alloys,  and  have  considerable  ductility.  The 
range  of  valuable  composition,  which,  in  the  copper-tin  alloys 
or  bronzes,  extends  over  a  variation  of  but  25  per  cent.,  covers 
a  range  of  50  per  cent,  in  the  list  of  brasses.  In  both  classes, 
a  sudden  and  great  variation  of  properties  is  observed  at  a 
certain  point,  and  the  maximum  and  minimum  are  not  far 
apart  in  either  the  brasses  or  the  bronzes. 

Alloy  No.  4  (copper,  82 ;  zinc,  18),  a  good  casting,  was  so 
ductile  that  it  could  not  be  broken  by  bending,  but  was  sawn 


382  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

apart  after  test.  Some  interesting  experiments,  exhibiting 
the  effect  of  prolonged  stress  on  the  brasses,  were  made,  which 
will  be  described  fully  later.  Maximum  tenacity  was  exhib- 
ited by  alloys  containing  about  40  per  cent,  zinc  (copper,  50), 
and  attained  nearly  55,000  pounds  per  square  inch  (nearly 
3,867  kilogs.  per  sq.  cm.).  The  highest  resistance  to  trans- 
verse stress  was  exhibited  by  the  alloy  copper,  47.7,  zinc,  52.3. 
The  softer  alloys  tested  by  tension  usually  stretch  not  only 
from  end  to  end  of  the  reduced  part  of  the  test-piece,  but 
also  in  the  heads  by  which  they  were  held  in  the  testing 
machine.  In  the  case  of  an  alloy  containing  39  per  cent,  zinc  ; 
61  copper,  a  peculiar  irregularity  of  elongation  during  test 
was  observed,  and  a  similar  phenomenon  was  noted  in  the 
deflection  of  the  same  alloy  under  transverse  loads.  Between 
40  and  50  per  cent,  zinc,  liquation  was  often  observed  to  oc- 
cur to  a  serious  extent. 

Tests  conducted  with  the  autographic  recording  machine 
were  concordant  with  those  made  by  tension,  and  the  quality  of 
the  metal  was  exhibited  fully  by  the  strain-diagrams  so  ob- 
tained. An  alloy  containing  89.8  per  cent,  copper  exhibited 
great  strength  combined  with  a  ductility  about  equal  to  that 
of  pure  tin.  An  exterior  fibre,  originally  parallel  to  the  axis, 
was  extended  to  3^  times  its  original  length.  Alloys  ap- 
proximating 90  per  cent,  copper  had  very  great  total  resili- 
ence. Alloys  containing  copper,  40,  zinc,  60,  were  extremely 
rigid,  extending,  in  some  cases,  less  than  o.oi  of  one  per  cent., 
and  even  as  little  as  0.00006  of  their  original  length.  Alloys 
containing  copper,  15,  zinc,  85,  were  subject  to  serious  loss  of 
strength  in  consequence  of  the  existence  of  minute  pores  in 
large  numbers,  which,  while  invisible  oftentimes,  may  injure 
the  casting  more  seriously  than  large  blow-holes  usually  weaken 
alloys  liable  to  them. 

When  testing  by  compression,  a  reduction  of  10  per  cent, 
in  the  length  of  the  ductile  alloys  was  made  the  limit,  but  the 
loads  causing  a  compression  of  5  and  of  20  per  cent,  and  up- 
ward, were  also  reported,  as  below.  One  of  the  silver-white 
alloys  was  found  to  be  the  strongest,  carrying  a  load  exceed- 
ing 120,000  pounds  per  square  inch  (over  8,436  kilogs.  on  the 
sq.  cm.). 


STRENGTH  OF  BRASSES.  383 

230.  Notes  taken  during  Tests  are  given  at  some  length 
in  the  report  on  this  investigation.  A  few  of  the  compo- 
sitions exhibit  properties,  as  thus  recorded,  which  may  be 
given  place  here.  In  tension  tests,  in  the  first  series,  maximum 
average  strength  is  given  by  bar  No.  9  (55.15  copper,  44.44 
zinc),  44,280  pounds  per  square  inch  (3,113  kilogs.  per  sq. 
cm.).  An  inspection  of  the  table  shows  that  this  average  re- 
sult is  reduced  by  liquation  in  bars  No.  8  and  No.  9,  as  No. 
8  B  (59.19  copper,  40.39  zinc)  and  No.  9  A  (59.13  copper, 
40.36  zinc)  have  nearly  the  same  composition  by  analysis  ; 
and  the  strength  of  these  pieces  is  much  higher  than  the 
average  of  the  two  pieces  of  either  No.  8  or  No.  9,  being 
51,380  and  53,660  pounds  per  square  inch  (3,612  and  3,772 
kilogs.  per  sq.  cm.),  respectively.  This  indicates  that  maxi- 
mum strength  is  possessed  by  an  alloy  containing  less  than 
44  per  cent.  zinc.  Transverse  tests  showed  the  maximum 
transverse  resistance  to  be  exhibited  by  bar  No.  n  (47.56 
copper,  52.28  zinc),  but  this  is  not  confirmed  by  tests  made 
subsequently  by  either  tensile,  transverse,  or  torsional  stress. 

Bar  No.  12  (41.30  copper,  58.12  zinc)  confirmed  the  results 
obtained  by  the  transverse  test,  showing  an  entirely  different 
metal  from  the  preceding.  It  was  weak  and  brittle.  The 
metal  was  so  hard  that  the  pieces  could  not  be  turned  in  the 
lathe,  and  were  therefore  tested  in  their  original  square  sec- 
tions. No.  12  A  broke  at  4,324  and  No.  12  B  at  3,130  pounds 
per  square  inch  (3,040  and  2,200  kilogs.  per  sq.  cm.).  No  at- 
tempt was  made  to  measure  the  elongations ;  they  were  ex- 
tremely small.  The  fractures  were  precisely  like  that  ob- 
tained by  transverse  stress. 

The  minimum  tenacity,  1,774  pounds  per  square  inch  (1,247 
kilogs.  per  sq.  cm.),  was  exhibited  by  bar  No.  14  A  (31.17 
copper,  67.84  zinc),  one  piece  only  being  tested.  The  aver- 
age tensile  strength  of  No.  13  (36.62  copper,  62.78  zinc),  which 
showed  the  lowest  transverse  strength,  was  but  little  higher, 
being  2,656  pounds  (1,867  kilogs.  per  sq.  cm.) 

The  curves  of  strength  of  the  first  and  second  series  show 
a  generally  close  agreement,  except  in  the  highest  part  of  two 
curves,  which  are  not  found  to  indicate 

^.^w^t     UW{^ 

CPTHE  ^ 

UNIVERSITY 

OF 


384  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

of  the  bar  of  maximum  strength.  The  curve  of  the  second 
series  probably  is  most  nearly  the  true  one. 

In  the  series  of  No.  29  (63.44  copper,  36.36  zinc),  No.  29 
A  broke  at  48,760,  and  No.  29  B  at  46,840  pounds  per  square 
inch  (3,437  and  3,293  kilogs.  per  sq.  cm.),  after  elongations  of 
31  and  32.4  per  cent.,  respectively.  The  fractures  were  of 
a  light  brownish-yellow  color,  and  very  compact  and  homo- 
geneous. The  plane  of  fracture  was  inclined  to  the  axis,  as 
with  most  of  the  pieces,  and  the  surfaces  were  slightly  pol- 
ished. The  pieces  were  uniformly  ductile  throughout  their 
whole  lengths,  as  was  shown  by  the  uniform  decrease  of  di- 
ameter as  the  pieces  elongated.  In  testing  No.  29  A,  a  sudden 
dull  sound  was  several  times  emitted  from  the  piece,  and  at 
the  same  instant  the  resistance  decreased,  in  one  case,  1,300 
pounds  (600  kilogs.,  nearly).  This  may  be  due  to  interior 
molecular  action,  of  the  same  nature  as  that  which  produced 
the  crackling  sound  noted  in  some  transverse  tests,  or  the 
irregularity  in  the  increase  of  deflections  noted  in  others. 

No.  30  (58.49  copper,  41.10  zinc). — The  average  strength 
of  the  two  pieces  of  this  bar  was  higher  than  that  of  the  pre- 
ceding, and  the  highest  of  this  series.  No.  30  A  broke  at 
52,260  and  No.  30  B  at  48,640  pounds  per  square  inch  (3,674 
and  3,419  kilogs.  per  sq.  cm.),  after  elongations  of  10.18  and 
IO  per  cent.,  respectively,  showing  much  less  ductility  than 
the  preceding  bars,  with  greater  strength.  There  was  observ- 
able irregularity  in  the  increase  of  elongations  under  increase 
of  load,  which  corresponds  with  the  irregularity  of  deflection 
observed  in  the  transverse  test  of  the  same  bar. 

Heat  was  generated,  in  some  cases  of  test  by  tension,  suf- 
ficient to  make  it  uncomfortable  to  hold  the  broken  end  of 
the  test-piece  in  the  hand.  This  was  observed  to  be  most 
noticeable  in  alloys  containing  rather  less  than  75  per  cent, 
copper.  While  testing  an  alloy  containing  63  per  cent,  cop- 
per, sudden  depressions  of  resistance  were  occasionally  ob- 
served accompanied  by  dull  sounds  probably  due  to  internal 
molecular  disruption. 

231.  The  Tenacity  of  Brass  may  be  roughly  reckoned, 
when  the  proportion  of  copper  exceeds  one-half,  as  will  be 


STRENGTH  OF  BRASSES.  385 

seen  on  comparing  the  data  obtained  from  good  specimens 
of  brass,  as 

T  =  30,000  +  500  2. 

232.  In  Compression  Tests,  it  proved  that  No.  5  (76.65 
copper,  23.08  zinc)  was  much  stronger  than  either  of  those 
richer  in  copper,  requiring  42,000  pounds  per  square  inch 
(2,953  kilogs.  per  sq.  cm.)  to  cause  a  compression  of  10  per 
cent.  The  elastic  limit  was  apparently  passed  at  about  26,000 
pounds  per  square  inch  (1,448  kilogs.  per  sq.  cm.).  From  this 
point  the  curve,  after  turning  toward  the  horizontal,  proceeds 
in  a  nearly  straight  line,  but  slightly  convex  to  the  axis  of  ab- 
scissas till  a  compression  of  35  per  cent,  is  reached,  showing 
an  increase  of  the  ratio  of  load  to  compression,  and  indicating 
that  the  increase  of  diameter  which  is  given  by  the  compres- 
sion merely  tends  to  increase  the  strength  of  the  piece  op- 
posing a  greater  sectional  area  to  the  stress.  The  piece,  after 
35  per  cent,  compression,  was  bent  in  the  form  of  a  double 
curve.  On  continuing  the  compression,  the  bending  of  the 
piece  caused  it  to  offer  a  slightly  diminished  resistance,  a  di- 
agonal crack  appearing  on  one  side,  and  the  curve  again  shows 
a  curvature  concave  to  the  axis  of  abscissas. 

On  continuing  the  compression,  after  140,000  pounds  per 
square  inch  (9,842  kilogs.  per  sq.  cm.)  of  original  section  had 
been  applied,  the  compression  amounting  to  5  2.9  per  cent., 
the  resistance  decreased  to  110,000  pounds  (7,733  kilogs.), 
probably  in  consequence  of  the  weakening  produced  by  the 
presence  of  the  crack.  The  piece  was  then  removed,  the  total 
compression  being  57.5  per  cent.  The  piece  after  removal 
measured  only  0.87  inch  in  length,  and  two  diameters  at  the 
middle  of  the  specimen  measured  1.03  inches  and  0.91  inch, 
the  section  being  approximately  elljptical. 

The  turned  surface  was  slightly  roughened  by  the  com- 
pression. 

No.  8  (60.94  copper,  38.65  zinc)  proved  to  be  much  stronger 
than  No.  5,  the  load  required  to  produce  a  compression  of  10 
per  cent,  being  75,000  pounds  per  square  inch  (4,956  kilogs. 
25 


386  MATERIALS  OF  ENGINEERING-NON-FERROUS  METALS. 

per  sq.  cm.).  The  elastic  limit  was  apparently  reached  at 
30,000  pounds  per  square  inch  (2,109  kilogs.  per  sq.  cm.),  after 
a  compression  of  1.25  per  cent.  After  passing  the  elastic 
limit,  the  resistance  again  became  nearly  proportional  to  the 
load,  the  ratio  being  much  less  than  before.  The  piece  be- 
came slightly  bent  and  the  surface  somewhat  roughened  by 
the  strain.  After  a  compression  of  24.8  per  cent.,  the  maxi- 
mum resistance  to  this  compression  being  99,000  pounds  per 
square  inch  (7,000  kilogs.  per  sq.  cm.),  the  resistance  decreased 
in  consequence  of  the  bending  of  the  specimen.  When  the 
piece  was  removed  after  a  compression  of  26.95  per  cent,  its 
diameter  was  found  to  have  increased  to  about  0.73  inch. 

No.  9  (55.15  copper,  44.44  zinc)  was  somewhat  stronger 
than  No.  8,  a  compression  of  10  per  cent,  being  caused  by 
78,000  pounds  per  square  inch,  and  breaking  at  136,000(5,883 
and  9,561  kilogs.  per  sq.  cm.),  after  a  compression  of  22.6  per 
cent.  The  elastic  limit  apparently  was  reached  at  about 
30,000  pounds  per  square  inch  (2,109  kilogs.  per  sq.  cm.).  At 
136,898  pounds  (9,625  kilogs.),  after  a  compression  of  about 
23  per  cent.,  the  piece  suddenly  gave  way,  a  small  piece 
shearing  diagonally  from  the  upper  end.  The  piece  had  be- 
come slightly  bent  under  the  stress  before  rupture  occurred, 
and  this  bending  may  partly  account  for  the  breaking,  as,  in 
consequence  of  the  bending,  the  stress  was  brought  upon  one 
side  of  the  upper  surface  and  was  not  distributed  evenly  over 
the  whole  surface.  The  diameter  of  the  piece  was  increased 
to  about  0.71  inch. 

No.  10  (49.66  copper,  50.14  zinc)  had  a  much  greater  re- 
sistance to  a  given  deflection  than  No.  9,  a  compression  of  10 
per  cent,  being  caused  by  117,400  pounds  per  square  inch 
(8,253  kilogs.  per  sq.  cm.),  and  fracture  occurring  in  precisely 
the  same  manner  as  that  of  No.  9  at  123,860  pounds  (8,707 
kilogs.  per  sq.  cm.),  after  a  compression  of  11.25  Per  cent. 
The  elastic  limit  appears  to  have  been  reached  at  about  40,000 
pounds  (2,812  kilogs.),  but  the  point  is  not  clearly  defined. 
The  diameter  was  increased  to  about  0.71  inch  before  break- 
ing, being  nearly  uniform  throughout  the  length.  The  surface 
was  very  slightly  wrinkled  by  the  compression. 


STRENGTH  OF  BRASSES.  387 

No.  II  (47.56  copper,  52.28  zinc)  was  much  stronger  than 
any  other  of  the  series  tested,  breaking  at  138,528  pounds  per 
square  inch  after  a  compression  of  13.6  per  cent.,  a  compres- 
sion of  10  per  cent,  being  produced  by  121,000  pounds  (9,740 
and  8,506  kilogs.  per  sq.  cm.).  The  elastic  limit  was  reached 
at  about  35,000  pounds  (2,460  kilogs.).  The  behavior  of  this 
piece  before  fracture  was  almost  exactly  like  that  of  No.  10, 
as  is  shown  by  the  close  agreement  of  their  curves.  The 
fracture  took  place  by  shearing  diagonally  across  the  speci- 
men just  above  the  middle.  The  diameter  was  increased  by 
the  compression  to  about  0.67  inch. 

No.  15  (25.56  copper,  74.00  zinc)  exhibited  a  behavior 
under  compression  very  different  from  that  of  the  piece  pre- 
viously tested.  It  broke  at  1 10,822  pounds  per  square  inch 
(7,791  kilogs.  per  sq.  cm.),  after  a  compression  of  5.85  per  cent. 
An  elastic  limit  was  apparently  reached  at  about  80,000  pounds 
per  square  inch  (5,624  kilogs.  per  sq.  cm.),  the  ratio  of  com- 
pression to  load  after  this  point  being  very  much  greater  than 
it  was  before  this  load  was  reached,  as  is  plainly  shown  by 
the  curve.  After  110,822  pounds  (7,791  kilogs.)  had  been 
reached,  the  compression  being  4.8  per  cent.,  the  resistance 
decreased  to  107,562  pounds  (7,563  kilogs.  per.  sq.  cm.),  as 
the  compression  increased  105.85  per  cent.,  and  the  piece  then 
suddenly  broke,  the  upper  half  flying  into  several  fragments, 
a  wedge-shaped  piece  being  apparently  formed  at  the  top 
which  seemed  to  split  open  the  lower  portion.  The  diameter 
was  increased  to  0.635  inch  by  the  compression,  as  measured 
after  breaking,  on  the  lower  part  of  the  specimen. 

233.  In  Transverse  Tests,  which  were  the  first  in  order, 
an  examination  of  the  cast  bars  of  the  first  series  showed  bars 
Nos.  i,  2,  and  3  (3.79  to  10.09  zinc)  to  be  defective,  and  the 
results  are  not  considered  conclusive  as  to  the  properties  of 
the  metal.  These  bars  were  soft  and  spongy,  and,  in  places, 
showed  signs  of  oxidation.  It  appears  probable  that  the  de- 
fective structure  of  these  bars  is  due  to  the  method  of  cast- 
ing, which  was  not  suitable  for  these  compositions,  and  is 
probably  not  necessarily  an  inherent  defect  of  metals  of  these 
compositions  properly  cast.  In  the  second  series  the  same 


388  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

peculiarity  was  observed  in  the  transverse  tests  of  alloys  con- 
taining small  proportions  of  zinc  (less  than  12.5  per  cent.)  with 
one  exception,  a  bar  containing  7.5  per  cent.  This  indicates 
that  it  may  be  quite  possible  to  secure  good  castings  of  alloys 
containing  small  percentages  of  zinc,  provided  the  proper 
conditions  are  discovered  and  observed. 

The  causes  of  the  formation  of  blow-holes  and  of  oxida- 
tion have  not  been  determined.  It  would  seem  that  the 
strength  of  sound  castings  of  these  metals  should  approach 
that  of  those  having  higher  percentages  of  zinc.  The  curve 
is,  therefore,  continued  in  a  straight  line  from  pure  copper  to 
No.  4  (81.99  copper,  17.99  zinc). 

All  alloys  of  copper  and  zinc  containing  less  than  55  per 
cent,  of  zinc,  may  be  considered  as  included  in  the  first  class, 
or  useful  alloys,  which  are  all  distinguished  by  a  yellow 
color. 

The  forms  of  the  curves  of  strength  indicate  that  the  first 
class  of  alloys  might  be  divided  into  two  divisions,  one  show- 
ing considerably  greater  strength  than  the  other.  The  first 
division  includes  those  from  No.  4  to  No.  7  (17.99  t°  33- 50 
zinc)  inclusive,  with  also,  probably,  Nos.  I,  2,  and  3,  or  all 
the  alloys  from  pure  copper  to  those  containing  33.50  zinc. 
These  show  a  modulus  of  rupture  from  21,000  to  28,000  (1,476 
to  1,968  kilogs.  per  sq.  cm.),  increasing  slightly  with  the  per- 
centage of  zinc.  They  are  also  characterized  by  great  duc- 
tility and  fibrous  or  earthy  fracture.  The  second  division  in- 
cludes bars  No.  8  to  No.  II,  inclusive  (38.65  to  52.28  zinc), 
which  show  much  greater  strength  than  the  preceding,  the 
modulus  of  rupture  of  No.  8  being  38,968,  and  that  of  No.  II 
48,471  (2,740  and  3,407  kilogs.  per  sq.  cm.),  and  less  ductility. 
The  fractured  surfaces  of  No.  8  and  No.  9  (60.94  copper,  38.65 
zinc,  and  55.15  copper,  44.44  zinc)  resemble  in  appearance 
those  of  No.  7  (66.27  copper,  33.50  zinc),  being  earthy  or 
fibrous,  but  having  a  darker  color.  The  fractures  of  No.  10 
and  No.  11  (49.66  copper,  50.14  zinc,  and  47.56  copper,  52.28 
zinc)  are  very  different  from  those  of  bars  containing  less  zinc, 
having  a  granular  structure  and  lustrous  surface  of  fracture. 
The  modulus  of  rupture  of  No.  10  is  much  less  than  that  of 


STRENG  TH  OF  BRA  SSES.  3  89 

the  other  three  bars  of  this  portion  of  the  series,  Nos.  8,  9,  and 
11,  but  this  is  probably  exceptional,  as  the  fracture  indicates 
defective  structure. 

No  II  (47.56  copper,  52.28  zinc)  gave  the  highest  modulus 
of  rupture  of  the  series,  48,471  pounds  (3,407  kilogs.),  and  this 
would  indicate  the  maximum  strength  of  the  series ;  but  this 
result  is  not  confirmed  by  other  tests  of  the  same  bar,  nor  by 
any  of  the  tests  of  the  second  series.  These  all  indicate  that 
the  point  of  maximum  strength  lies  between  No.  8  and  No.  9 
(38.65  and  44.44  zinc).  The  moduli  of  rupture  of  Nos.  8,  9 
and  10,  although  much  higher  than  those  of  the  bars  contain- 
ing less  zinc,  are  lower  than  those  of  nearly  similar  composi- 
tion in  the  second  series,  but  the  reason  of  this  is  not  ap- 
parent. 

Between  bar  No.  11  (47.56  copper,  52.28  zinc)  and  bar  No. 
12  (41.30  copper,  58.12  zinc)  there  is  a  sudden  change  of  prop- 
erties. Nos.  12,  13,  and  14  (58.12  to  66.23  zinc)  represent 
the  second  class  of  the  copper-zinc  alloys-,  which,  as  noted  in 
describing  the  external  appearance  of  the  bars,  is  distinguished 
by  a  nearly  white  color,  vitreous  fracture,  and  very  brilliant 
lustre,  and  also  by  great  weakness  and  lack  of  ductility.  They 
correspond  closely  in  all  their  properties  to  the  silver-white 
alloys  of  copper  and  tin.  The  minimum  strength  is  given  by 
bar  No.  13  (36.62  copper,  62.78  zinc),  its  modulus  of  rupture 
being  only  about  one-tenth  of  that  of  the  maximum,  bar  No. 
ii  (47.56  copper,  52.28  zinc),  which  differs  from  it  in  compo- 
sition only  about  20  per  cent. 

Bar  No.  15  (25.77  copper,  73.45  zinc)  shows  a  very  much 
greater  strength  than  No.  14,  and  marks  the  boundary  of  the 
third  class,  which  includes  all  the  bars  containing  more  than 
73.43  per  cent,  of  zinc.  This  class  is  distinguished  by  a  blu- 
ish-gray color,  and  finely  granular  structure,  which  becomes 
crystalline  as  the  composition  approaches  pure  zinc,  and  a 
much  greater  strength  than  the  second  class,  although  not  so 
great  as  the  first  class,  the  yellow  and  useful  metals. 

There  is  a  somewhat  irregular  increase  of  strength  from 
No.  15  to  No.  19  (73.45  to  88.88  zinc).  The  latter  represents 
the  point  of  "  second  maximum  "  strength  in  the  series,  which 


3QO    MATERIALS  OF  ENGINEERING— ^7ON-FERR O US  METALS. 

corresponds  to  the  second  maximum  of  the  copper-tin  alloys. 
From  bar  No.  19  there  is  a  regular  and  rapid  decrease  of 
strength  to  pure  zinc,  which  represents  the  "  second  minimum/' 

It  will  be  noted  that  the  curve  of  transverse  strength  of 
the  copper-zinc  alloys  is  not  nearly  as  regular  as  that  of  the 
alloys  of  copper  and  tin  ;  but  in  many  respects  the  two  curves 
show  a  marked  resemblance.  The  most  striking  contrast  be- 
tween the  two  curves  is  the  much  greater  range  of  composi- 
tion of  the  useful  metals  among  the  copper-zinc  alloys,  the 
curve  of  copper-tin  alloys  showing  that  the  useful  metals  are 
all  comprised  within  the  limits  of  less  than  25  per  cent,  of 
tin,  while  in  the  copper-zinc  alloys  the  useful  metals  may 
contain  as  much  as  52  per  cent,  of  zinc.  A  sudden  decrease 
of  strength  takes  place  at  a  definite  point  in  both  sets  of  al 
loys,  and  the  curves  are  in  this  respect  similar.  The  bars  of 
minimum  strength  of  both  are  also  similar  in  their  properties. 
The  point  of  minimum  strength  is  very  near  the  point  of 
maximum  strength  in  both  curves.  That  part  of  the  curve 
which  represents  the  third  class  of  alloys  of  copper  and  zinc, 
corresponds  with  the  curve  of  those  copper-tin  alloys  which 
contain  more  than  50  per  cent,  of  tin,  and,  like  it,  shows  a 
second  maximum;  but  it  shows  that  the  alloys  containing  a 
large  amount  of  zinc  have  much  greater  strength  than  alloys 
containing  a  large  amount  of  tin.  The  former  are  also  much 
harder  than  the  latter. 

The  transverse  tests  of  the  second  series  indicate  the  same 
relations  between  strength,  ductility,  and  composition  that 
were  noted  in  tests  of  the  first  series. 

From  bars  No.  22  to  No.  28  (1.88  to  30.06  zinc),  inclusive 
(excepting  bars  No.  22  and  No.  24  as  defective),  there  is  a 
very  gradual  increase  in  the  modulus  of  rupture.  Bars  No. 
29  and  No.  30  (36.36  and  41.10  zinc)  show  a  rapid  increase  in 
strength  over  the  preceding;  the  corresponding  moduli  of 
rupture  are  respectively  43,216  and  63,304  pounds  (1,296  and 
4,450  kilogs.  per  sq.  cm.),  the  latter  being  the  maximum 
modulus  of  rupture  of  the  series.  This  maximum  does  not 
correspond  with  that  of  transverse  tests  of  the  first  series,  but 
is  confirmed  by  all  the  other  tests. 


STXENG  TH  OF  BRA  SSES.  39 1 

234.  Tests  by  Torsion  confirm  the  results  obtained  and 
deductions  made  from  the  other  experiments : 

From  No.  4  to  No.  n  (17.99  to  52-2%  Per  cent,  zinc)  the 
average  strength  of  all  the  pieces  is  quite  high,  the  curve  con- 
firming the  curve  of  tensile  results  almost  exactly,  and  indi- 
cating the  character  of  the  first  class,  or  useful  alloys. 

Between  No.  n  and  No.  12  (52.28  and  58.12  zinc)  a  very 
sudden  decrease  of  strength  takes  place,  and  Nos.  12,  13,  and 
14  (58.12  to  66. 23  zinc)  show  very  low  torsional  strength,  these 
metals  being  in  the  second  class,  or  silver-white  and  brittle 
alloys. 

From  No.  15  (25.77  copper,  73.45  zinc)  to  the  end  of  the 
series  (pure  zinc)  the  torsional  tests  indicate  the  characteris- 
tics of  the  third  class,  showing  greater  strength  and  ductility 
than  the  second  class,  the  latter  quality  increasing  toward 
pure  zinc,  and  the  strength  reaching  a  maximum  at  No.  19 
(10.30  copper,  85.10  zinc). 

No.  II  (47.56  copper,  52.28  zinc)  gave  a  strain-diagram 
similar  in  form  to  that  of  soft  cast  iron  or  hard  bronze,  and 
very  different  from  those  obtained  from  alloys  richer  in  cop- 
per. Of  No.  12  (41.30  copper,  58.12  zinc)  two  pieces  only 
were  tested.  The  results  correspond  with  those  of  tensile 
and  transverse  tests,  showing  that  the  metal  is  extremely 
weak  and  brittle.  The  fractures  were  silver-white,  vitreous, 
and  conchoidal.  The  pieces  were  too  hard  and  brittle  to  be 
turned  in  the  lathe,  and  were  shaped  by  grinding  with  an 
emery  wheel.  The  ductility  is  extremely  slight,  the  exten- 
sion of  a  line  of  particles,  one  inch  long  in  the  surface  parallel 
to  the  axis,  being  only  0.00006  inch. 

No.  130  (36.52  copper,  63.20  zinc)  was,  if  possible,  even 
weaker  and  more  brittle  than  No.  12.  Only  one  piece  was 
tested  and  this  was  not  brought  to  a  cylindrical  form,  but 
was  tested  in  its  original  square  section.  The  strength  was 
much  less  than  that  of  any  other  piece  of  the  series,  showing 
the  composition  containing  63.20  zinc  to  be  about  that  of 
minimum  strength.  The  strain-diagram  was  a  straight  and 
nearly  vertical  line.  Of  No.  33  (43.36  copper,  56.22  zinc)  two 
pieces  only  were  tested.  They  were  too  hard  to  be  turned 


3Q2  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

in  the  lathe,  and  also  were  shaped  by  an  emery  wheel.  The 
torsional  moments,  after  being  reduced  to  the  equivalents  of 
those  of  pieces  of  standard  diameters,  were  much  less  than 
those  of  the  preceding  bars.  The  appearance  of  the  fractures 
also  showed  as  great  a  difference  in  the  structure  of  the  metal 
as  was  indicated  by  the  difference  in  strength.  Both  fract- 
ures were  diagonal,  but  No.  33  A  was  of  a  pinkish  gray  color 
and  finely  granular  structure,  and  No.  33  B  was  of  a  brilliant 
silver-white  color,  smooth  and  vitreous.  The  analyses  of  the 
turnings  of  the  tension  pieces  show  that  the  difference  was 
due  to  liquation  ;  No.  33  A  containing  55.89  per  cent,  zinc, 
and  No.  33  B  56.55  per  cent,  zinc.  The  fact  that  so  small  a 
difference  in  the  percentage  of  zinc  should  make  such  a  great 
difference  in  properties  is  evidence  of  the  very  rapid  though 
continuous  change  which  takes  place  on  the  boundary  line 
between  the  first  and  second  classes  of  the  copper-zinc  alloys, 
and  which  is  plainly  shown  by  the  rapid  fall  of  that  portion 
of  the  curve  corresponding  to  alloys  of  about  this  composi- 
tion. 

235.  Brass  Shafts  and  spindles  subjected  to  torsion  may 
be  calculated  by  the  formula 


i^f/^JL% 


given  in  Chapter  VIII.,  Art.  166,  in  which  s  varies  from  5,000  to 
60,000,  according  to  composition  and  soundness  of  the  alloy. 
If  A^  is  taken  to  measure  the  difference  between  the  percen- 
tage of  zinc  present  and  that  of  maximum  resistance,  45  per 
cent.,  a  rough  estimate  may  be  taken,  as 

s,  =  50,000  -  333  A z 
when  the  alloy  contains  less  zinc,  and 

s\  —  50,000  —  3,000  A  z 
between  z  =  45  per  cent,  and  z  =  60  per  cent. 


STRENGTH  OF  BRASSES.  393 

In  metric  measures, 

s*m  =  3,5^5  -  24 A*; 
s\m  =  3,515  -  211  A*. 

236.  The  Records  of  Tests  of  a  selected  number  of  cop- 
per-zinc alloys  are  here  given,  and  those  of  several  others  are 
presented  later  when  considering  the  effect  of  prolonged 
stress  on  this  class  of  materials.  These  records  are  extracted 
from  the  set  presented  to  the  U.  S.  Board  and  printed  in  the 
report  of  that  body.  Each  record  is  accompanied  by  memo- 
randa relating  to  the  conditions  of  test  and  details  of  the  ex- 
periment which  render  further  explanation  unnecessary. 


TABLE  LXXIII. 

TESTS   BY  TENSILE   STRESS. 

Alloys  of  Copper  and  Zinc. — Dimensions. — Length  =  5"  ;  diameter  =0.798". 

BAR  NO.  25  B. 

COMPOSITION. — Original  mixture :  Cu,  82.5  ;  Zn,  17.5.    Analysis :  Cu,  83.00 ;  Zn,  16.90. 


K 

«o 

2o 

" 

\ 

^ 

2fc 

2 

z 

CO 

o  S 

0  * 

0)   .g 

Z  M 

o  w 

0  * 

K  X 

r  S 

SET. 

1*  Ij  9C 

V.  - 

p  s 

SET. 

**  W  jg 

£* 

<  u 

<       o 

£5 

<^ 

<        0 

3 

3 

H 

M 

3 

g  K  Z 

|aa 

H 

Pounds. 

Inch. 

Inch. 

1  Pounds. 

/ffoi. 

Inch. 

1,000 

0.0014 

0.03 

17,000 

0.3194 

6-39 

2,000 

0.0037 

.     . 

0.07 

18,000 

0.3600 

7.20 

4,000 

0.0104 

. 

0.21 

19,000 

0.4034 

. 

8.07 

200 

o  oo  7 

.... 

20,000 

0.4460 

8.92 

6,000 
7,000 

0.0230 
0.0326 

• 

0.46 
0.65 

200 
2I,OOO 

0.4892 

o  4404 

9'.78 

8,000 

200 

9,000 

10,000 
11,000 
12,000 
200 

0.0412 

0.0500 
0.0616 
0.0840 
0.1154 

0  0   22 
0         00 

0.82 
1.  00 

1.23 

1.68 
2.31 

22,000 
23,000 
24,000 
32,800 

Total  el< 

LI/': 

Diametei 

0.5274 

Measuring  a 
Broke  2  inch 
>ngation  mea 
=  23.4  per  cen 
of  fractured 

10.55 
11.17 
pparatus  slipped, 
es  from  D  end. 
sured   after  breaking, 

section.  0.608". 

13,000 

0.1483 

2.97 

Tenacity  per  square  inch   original   section, 

14,000 
15,00-0 
16,000 

0.1883 
0.2344 
0.2747 

3.76 
4.69 
5-49 

^2,800  pounds. 
Tenacity  per  square  inch  fractured  section, 
56,493  pounds. 

2OO 

o  2676 

394  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE    LXXIII.— Continued. 

BAR   NO.  26   B. 

COMPOSITION. — Original  mixture  :  Cu,  72.5  ;  Zn,  27.5.    Analysis:  Cu,  75.65  ;  Zn,  24.15. 


H 

^ 

h 

a 

m 

g 

«  o 

K 

•z 

Z  o 

w  ffi 

|| 

l|, 

ls. 

§| 

§*    . 

v.  5 

£5 

SET. 

K   (J 

P 

SET. 

|g| 

Q 

3 

og3 

i" 

3 

a 

u 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

2,000 

o  0040 

O.o8 

19,000 

0.3326 

6  6e 

3,000 

•     7 
0.0062 



0.12 

20,000 

0.3834 

U.v.^ 
7.67 

4,000 

O.OIOO 

0.20 

200 

0-3724 

5,000 

0.0144 



0.29 

21,000 

0-4334 

8.67 

6,000 

0.0215 

o.  43 

22,OOO 

0.4846 

96O 

7,000 

0.0209 

jj 
0.60 

23,000 

0.5380 

.uy 
10.76 

8,000 

0.0368 



0.74 

24,000 

0.5938 

11.88 

200 

0.0221 

200 

0.5788 

9,000 

10,000 

0-0443 
o  .  05  i  8 



0.89 
i  .04 

25,OOO 
26,OOO 

0.6480 
0.71  s6 

12.96 

TA      OT 

11,000 
I2,O~O 

0.0646 
0.0698 

1.29 
1.40 

27,000 
36,840 

Measuring  apparatus  slipped. 
Broke  2  inches  from  B  end. 

200 

0.0636 

Total  elongation  measured    after  breaking, 

13,000 
14,000 

0.0878 
°-XI33 

1.76 

2.27 

1.27"  •=  25.4  per  cent. 
Diameter  of  fractured  section,  0.587". 

15,000 

0.1513 

3-03 

Tenacity  per  square  inch,  original  section, 

l6,OOO 
200 

0.1867 

0.1784 

3-73 

36,840  pounds. 
Tenacity  per  square  inch,  fractured  section, 

17,000 

0.2348 

4.70 

68,064  pounds. 

l8,OOO 

0.2813 

5-^3 

BAR  NO.  2Q   B. 

COMPOSITION.— Original  mixture:  Cu,  62.5  ;  Zn,  37.5.    Analysis  :  Cu,  63.52  ;  Zn,  36.26. 


1,000 

O.OOII 

O.O2 

25,000 

o.  2097 

4.19 

2,000 

0.0034 

0.07 

26,000 

0.2371 

4-74 

3,ooo 

0.0055 



O.II 

27,000 

0.2668 

5-34 

4,000 

0.0078 

O.l6 

28,OOO 

0.2961 

5.92 

5,000 

0.0100 



0.20     ; 

200 

0.2784 

6,000 

O.OI2I 



0.24 

29,000 

0.3287 

6^57 

7,000 

0.0142 

0.28 

30,000 

0.3665 

7-33 

8,000 

0.0166 



0-33 

3I,OOO 

0.3988 

7.98 

9,000 

0.0191 

0.38 

32,000 

0.4260 

8.52 

10,000 

0.0218 



0.44 

200 

0.4252 

11,000 

0.0257 

0.51 

33,000 

0.4790 

9-58 

12,000 

0.0293 

0-59 

34,000 

0.5173 

Jo.  35 

200 

0.0075 

35i°oo 

o.5585 

11.17 

13,000 

0.0336 

0.67 

36,000 

o  .  6090 

12  18 

14,000 

0.0392 

0.78 

200 

o'.5886 

15,000 

16,000 

200 

0.0452 
0.0520 

0.0322 

0.90 

1.04 

37,000  , 
Measunr 
47,840 

o  .  6548 
g  apparatus  s 
Broke  i  inch 

lipped, 
from  B  end. 

13.10 

17,000 
18,000 
19,000 

0.0643 
0.0678 

O.o3l2 

:::::: 

1.29 
*-35 
1.62 

Total  elongation  measured    after  breaking. 
1.62"  =  32.4  per  cent. 
Diameter  of  fractured  section,  0.656". 

20,000 
200 

0.1061 

0.0814 

2.12 

The  piece  drew  down  very  uniformly  through 
the  whole  length  to  a  diameter  of  about 

21,000 

0.1142 



2^28 

0.685". 

22,000 

0.1350 

2.70 

Tenacity  per  square  inch,  original  section, 

23,000 

0.1571 

3-14 

47,840  pounds. 

24,000 

0.1836 

3-67 

Tenacity  per  square  inch,  fractured  section, 

200 

0.1683 

70,772  pounds. 

STRENG  TH  OF  BRA  SSES.  395 

TABLE  LXXIII.—  Continued. 

BAR  NO.  4  A. 

COMPOSITION.— Original  mixture  :  Cu,  80;  Zn,  20.    Analysis  :  Cu,  81.97  ;  Zn,  17.95. 


LOAD  PER  SQUARE 
INCH. 

ELONGATION  IN  5 
INCHES. 

SET. 

[ill 

LOAD  PER  SQUARE 
INCH. 

ELONGATION  IN  5 
INCHES. 

SET. 

iii 

Pounds. 
1,600 

2,000 

3.000 
4,200 
5,000 
6,000 
7,000 
8,000 

120 

9,000 

10,000 
11,000 

12,000 

120 

13,000 

14,000 
16,000 

12O 

18,000 

20,000 

Elongatio 
Elongatio 

IOO 
22,000 
24,000 
26,000 

O.OOIO 
O.OO2O 
0.0040 
0.0065 
0.0077 
0.0106 
0.0139 
0.01/5 

0.0223 
0.0200 
0.0424 
0.0626 

0.0895 

0.1337 
0.2227 

0.3253 

n  increased  in 
n  increased  in 

0.5809 
0.7.83 
0.8504 

Inch. 

O.O2 
0.04 
0.08 
0.13 
O.IS 
0.21 
0.23 
0.35 

0.45 

0.85 
1.25 

1.79 

2.67 

4-45 

8.92 
V- 
'5- 

liife 
14.37 
17.01 

Pounds. 

30,000 
30,400 
30,600 

measui 
conseq 
square 
Continue 
tions,  2 
at  32,  2c 
Total  ek 
1.52"  = 
Diametei 
Tenacity 
32,200  i 
Tenacity 

Ti^a 

differei 
made  £ 

At  fractu 
%  inch  fi 
i  inch  fr< 
2  inches 
3  inches 

Inches. 

1.3080 
At  this  poin 
ing   instrume 
uence  of  the 
head  of  the  si 
d  the  test  wit! 
ind  the  piece 
o  pounds  per 
mgation  as  m 
30.40  per  cen 
•  of  fractured 
per  square 
>ounds. 
per  square  i 
>ounds. 
wing  measur 
it    portions  o 
liter  breaking 

red  surface... 
'om  fracture. 

Inch. 

25.05 
26.16 

igs  of  the 
loose,  in 
vn  of  the 

\?  el°SSf  ' 
.he  middle 

breaking, 

1  section, 
d  section, 

ameter  of 
nen  were 

Cend. 

0^698 
0.708 
0.720 

the  fastenii 
nts    became 
drawing  doi 
>ecimen. 
lout  measurii 
broke  near 
square  inch. 
:asured  after 
t. 
section,  0.585 
inch,  origins 

nch,  fracture 

ements  01  di 
f    the    specii 

A  end. 
0.585' 

0.0099 

0.0610 

0.2204 

2  m.  to  0.45^ 
4  m.  to  0.45; 

5m  fracture  0.712 

'rom  fracture  0.710 
'rom  fracture  0.710 

BAR  NO.  5  A. 

COMPOSITION.—  Original  mixture  :  Cu,  75  ;  Zn,  25.    Analysis  :  Cu 

,  77.84  ;  Zn,  21.78. 

800 

O.OOIO 

0.02 

22,000                   0.5820 

11.64 

1,200 

0.0020 

0.04 

24,000          0.7053 



14.11 

2,000 

3,000 

0.0043 
0.0073 



O.Og 
0.15 

25,000            0.7655 
26,000       Measuring  a 

pparatus  slip 

15-31 
ped  ;  con- 

4,000 

0.0096 

O.lg 

tinued    te 

;t   without  i 

neasurmg 

5,000 

0.0125 

0.25 

elongation 

s. 

6,000 
7,000 

0.0155 
0.0206 

0.31 
0.41 

34,040       Broke  J  inch  from  A  end 
Total  elongation,   measured  after 

breaking 

8,000 

200 

0.0250 

0.0143 

0.50 

1.80"  =  36  per  cent. 
Diameter  of  fractured  section,  0.585". 

9,000 

IO,OOt 
11,000 
12,000 
2OO 

0.0319 
0.0380 
0.0469 
0.0631 

0.0600 

0.64 
0.76       i 

°,% 

Tenacity  per  square  inch,  original  section, 
34,040  pounds. 
Tenacity  per  square  inch,  fractured  section, 
63,322  pounds. 
Diameters  after  breaking. 

13,000 

0.0933 

1.87 

Inch. 

2    65 

At  fracture. 

585 

14,000 

A.  6s 

i  inch  from  fracture 

0.232 

O    22O3 

2  inches  from  fracture. 

685 

' 

6  88 

3  inches  from  fracture. 

604. 

4  inches  from  fracture 

"  '28 

Elongation  increased  in  i  m.  to  0.4713". 
Elongation  increased  in  2  m.  to  0.4795". 

5  inches  from  fracture. 

MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE  LXXIIL— Continued. 

BAR   NO.  8    B. 

COMPOSITION.— Original  mixture  :  Cu,  60 ;  Zn,  40.    Analysis :  Cu,  59.19  ;  Zn,  40.39. 


Ed 
K 

m 

2£ 

a 

X 

m 

%  o 

Z 

I 

0 

lx- 

ij 

IL 

gri 

1  z 

~  u 

Ck    •"• 

o  2 

SET. 

PS* 

o     ° 

Ctf  U 

£2 

P 

SET. 

|ss 

Q 

< 

S 

u 

J 

w 

3 

w 

d 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

2,000 

0.0016 

0.03 

28,000 

0.2310 

4.62 

„  ooo 

o  .  0040 

0.08 

200 

0.2190 

4,000 

0.0063 

0.13 

30,000 

0.2648 

5-30 

e  2OO 

o.  15 

32,400 

o.  3235 

6.47 

6,OOO 

0.0103 

O.2I 

200 

0.3062 

7,000 

8,OOO 

0.0113 
0.0134 

0.23 
O.27 

34.000 
36,000 

0.3850 

0.4526 

7.70 

9.05 

200 

0.0008 

200 

0-4373 

9  OOO 

0.0152 

o.  30 

36,000 

0.4860 

9.72  • 

IO,OOO 

11,000 

12,000 
2OO 

0.0173 

0.0220 

0-35 
0.38 
0.44 

38,000  _ 

Measurm 

50,520 
51,380 

0.5700 

g  apparatus  s 
(Elongat'n  n 
Broke  in  mk 

ii  .40 

calipers). 

lipped, 
icasured  Witt 
Idle. 

0.0075 

i  -3  ooo 

O.O249 

o.  50 

Total  elongation,  measured  after  breaking, 

14,000 

0.0296 

0.59 

1.48"  =  29.6"  per  cent. 

16  ooo 

o  .  0406 

O.bl 

Diameters  of   fractured  section,  0.672"  and 

200 

0.0336 

0.678"  (elliptical). 

18,000 

20,000 
200 
22,OOO 

0.0545 
0.0773 

O.IIOO 

0.0716 

1.09 
2.20 

Diameter  of  piece  i  inch  from  fracture,  0,687". 
Tenacity  per  square    inch    original  section, 
51,380  pounds. 
Tenacity  per  square  inch  fractured  section, 

24,000 

0.1445 

2.89 

71,762  pounds. 

2OO 

0.1341 

26,000 

0.1960 

3-94 

BAR   NO.  9  A. 

COMPOSITION.—  Original  mixture  :  Cu,  55  ;  Zn,  45.    Analysis  :  Cu,  59.13  ;  Zn,  40.36. 

2,000 

0.0024 

O.O5 

200 

0.1091 

3,000 

0.0038 

0.08 

28,000 

0.1139 

2.28 

4,000 

0.0056 

O.  II 

30,000 

0.1489 

2.98 

200 

0.00l6 

32,000 

0.1791 

3.58 

5,000 

0.0072 

0.14 

200 



o.  1712 

.... 

6,000 

0.0086 



0.17 

36,000 

0.3017 

6.03 

7,000 

0.0102 

0.20 

40,000 

0.4236 

8.47 

8,000 

O.OII5 



0.23 

200 

0.4077 

200 

0.0027 

44,000 

0.6201 

12.40 

9,000 
10,000 

O.OI3I 
0.0137 

0.26 
0.27 

48,000 
53,660 

Measuring  apparatus  slipped. 
Broke  at  shoulder,  B  end. 

11,000 

0.0152 

0.30 

Total   elongation,  measured  after 

breaking. 

12,000 
2OO 

0.0167 

0.0082 

°-33 

1.27  =  25.40  per  cent. 
Diameter  of  fractured 

section.  0.675". 

13,000 

0.0l82 

0.36 

Diameter  of  piece  i  inch  from  fracture,  0.680". 

14,000 

O.O2OO 



0.40    p  Diameter  of    piece  3 

inches  from 

fracture, 

15,000 

0.0217 

•*.... 

0.43      j      0.680". 

16,000 

0.0240 

0.48     1    Diameter  of    piece  4 

inches  from 

fracture, 

200 

O.O2OI 

i 

0.687". 

17,000 

0.0259 

0.52 

Diameter  of   piece    5 

inches  from 

fracture, 

18,000 

0.0289 

0.58 

0.704". 

19,000 

0.0323 



0.65 

Diameter  of   piece  6 

inches  from 

fracture, 

2O,OOD 

0.0364 

0.73 

0.710". 

22,000 

0.0460 

0.92 

Tenacity  per  square   inch,  original  section, 

24,000 
26,000 

0.0614 
0.0832 



1.23 

1.66 

53,660  pounds. 
Tenacity  per  square  inch,  fractured  section, 

28,000 

0.1136 

1.27 

74,975  pounds. 

S  TRENG  TH  OF  BRA  SSES.  397 

TABLE  LXXIV. 

RECORD   OF   TESTS  BY   COMPRESSIVE  STRESS. 

Alloys  of   Copper  and   Zinc.      Dimensions  :  Length  =  2"    (5.08   cm.)  ; 
diameter  =  0.625"  (*5  cm.). 

BAR  NO.   2. 

COMPOSITION.— Original  mixture :  Cu,  90  ;  Zn,  10.    Analysis :  Cu.  9.56  ;  Zn,  90.42. 


H 

5§ 

H 
B 

2S 

LOAD. 

COMPRES- 
SION. 

Ii 

lit 

LOAD. 

COMPRES- 
SION. 

Ii 

px 

Q 

fsi 

ft*   ** 

a 

ggg 

- 

O 

8fcJ 

\ 

I*' 

Pounds. 

Inch. 

Pounds. 

Pounds. 

Inch. 

Pounds. 

500 

0.002 

1,630 

O.IO 

12,000 

0.294 

39,  'H 

14.70 

1,000 

2,000 

O.OO4 
0.009 

3,250 
6,519 

O.2O 
0.45 

13,000 
14,000 

0-334 
0.372 

42,373 
45-633 

16.70 
18.60 

3,000 

0.012 

9,778 

0.60 

15,000 

0.408 

48,892 

20.40 

4,ooo 

O.O22 

13,038 

1.  10 

16,000 

0.442 

52,152 

22.10 

S,000 
6,000 
7,000 

0.046 
0.083 
O.II9 

16,297 
'9,557 
22,816 

2.30 
4-15 

5-95 

17,000 
\     18,000 
19,000 

0.482 
0.530 
0.563 

55,4" 
58,671 
61,9^0 

24.IQ 
26.50 
28.15 

8,000 
9,000 

0.152 
0.187 

26,076 
29,335 

7.60 
9-35 

i     20,000 
Removec 

o-599 
I  piece  slight 

65,190 
Jy  bent,  sui 

,       29-95 

•face  very 

10,000 

0.225 

32,595 

ii  25 

rough. 

11,000 

0.262 

35,855 

BAR  NO.  5. 

COMPOSITION.— Original  mixture :  Cu,  75  ;  Zn,  25.    Analysis :  Cu,  76.65 ;  Zn,  23.08. 


2,000 

0.0085 

6,519 

0.43 

i       22,000 

0.476 

71,709 

23.80 

3,000 

0.013 

9,778 

0.65 

23.000 

0.502 

74,968 

25.10 

4,000 

0.016 

13,038 

0.80 

24,000 

0.528 

78,228 

26.40 

5,ooo 
6.000 
8,000 

0.019 

0.022 

0.032 

16,297 
26*076 

o.95 
t.lo 
l.6o 

26,OOO 
28.000 
30,000 

0.562 
0.613 
0.652 

84,747 
91,266 

28.10 
30.65 
32.00 

9,000 

10,000 

0.042 
0.065 

29,335 

32,595 

2.10 

3-25 

32,000 

34,ooo 

0.691 
0.734 

104!303 
110,823 

34-45 
36.70 

11,000 

0.109 

35,855 

5-45 

36,000 

0-773 

117,34* 

38.65 

12,000 

0.154 

39,  "4 

7.70 

38,000 

0.828 

123,860 

41.40 

13.000 

0.203 

10.15 

i     39,000 

0.876 

127,119 

43.80 

14,000 

0.243 

45,633 

12.15 

;     40,000 

0.916 

130,379 

45.8o 

15,000 

0.273 

48,892 

13.65 

41,000 

0.966 

133,638 

48.30 

16,000 

0.309 

'5  45 

42,000 

I.  Oil 

136,898 

50.55 

17,000 
18,000 

0.339 
0.366 

58,671 

is!  30 

43,000              1.058 
Resistance  decreased  t 

0— 

52.90 

19,000 

20,000 
21,000 

0.399 
0.424 
0.451 

61,930 
65,190 

68,449 

19-95 

21.20 
22-55 

34,000    1        1.150             110,822           57.^0 
Removed  piece  squeezed  out  of  shape  with  a 
diagonal  crack  on  one  side. 

3Q8  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE  LXXIV.— Continued. 

BAR    NO.  9. 

COMPOSITION.— Original  mixture:  Cu,  55  ;  Zn,  45.    Analysis:  Cu,  55.15  ;  Zn,  44.44. 


u 

Z  k 

Ed 

z  &. 

3 

a  o 

H 

-  o 

& 

Z  H 

a 

Z  H 

LOAD. 

COMPRES- 
SION. 

K  U 

u  z 

0  Z 

LOAD. 

COMPRES- 
SION. 

il 

jjjeJB 

e«  "-1 

q 

o 

111 

&1      N-t 

Q 

3 

m 

u 

Pounds. 

Inch. 

Pounds. 

Pounds. 

Inch. 

Pounds. 

1,000 

0.005 

3,259 

0.25 

20,000 

0.150 

65,190 

7-50 

2,000 

0.008 

6,5I9 

0.40 

22,000 

0.173 

71,709 

8.65 

3,ooo 
4,000 
5,000 
6,000 

O.OIO 
O.OI2 
0.014 

0.016 

9,778 
13,038 
16,297 

0.50 

O.CO 

0.70 

0.80 

24,000 
26,000 
28,OOO 
30,000 

O.2O2 
0.227 
0.253 
0.280 

78,228 
84,747 
91,266 
97,785 

10.10 

"•35 
12.65 
14.00 

7,000 

0.019 

22,816 

0.95 

32,000 

0.299 

I04'3°3 

14-95 

8,000 

0.023 

26,076 

34,000 

0-335 

110,822 

16.75 

9,000 

0.026 

29,335 

1.30 

36,000 

0.362 

"7,34i 

18,  10 

10,000 

0.032 

32,595 

1.60 

38,000 

0.388 

123,860 

19.40 

11,000 

0.040 

35,855 

2.00 

39,000 

0.405 

127,119 

20.25 

12,000 

0.050 

39,  "4 

2.5O 

40,000 

°-415 

T3°,379 

20.75 

13,000 
14,000 

0.061 
0.075 

42,373 

45,633 

3-05 

3-75 

41,000 
41,500 

0.436 
0.452 

•133,638 
135,268 

21.80 
22.60 

15,000 
16,000 

0.087 

O.IOO 

48,892 
52,152 

4-35 
5-00 

42,000 
Broke  su 

ddenly,  a  sm 

136,898 
all  piece  br< 

:aking  off 

17,000 

I<5,COO 

0.113 
0.121; 

55,4" 
58,671 

5.65 
6.25 

from  upper  corner. 
Bent  slightly. 

19,000 

0.138 

61,930 

6.90 

BAR  NO.  II. 


COMPOSITION.— Original  mixture :  Cu,  45 ;  Zn,  55.    Analysis:  Cu,  47.56  ;  Zn,  52.28. 


1,000 

O.OO2 

3,259 

O.IO 

26,000 

O.  IO2 

84,747 

5-io 

2,000 

O.OO7 

6,519 

0-35 

28,000 

0.115 

91,266 

5-75 

3,000 

O.OIO 

i9'778 

0.50 

30,000 

0.130 

97,785 

6.50 

4,000 

O.OI1 

o.SS 

32,000 

0.147 

*°4,393 

7-35 

5,000 

0.013 

16,297 

0.65 

34,000 

0.164 

110,822 

8.20 

6,000 

0.014 

19,557 

0.70 

36,000 

0.188 

117,341 

9.40 

7,000 

0.016 

?2,8t6 

0.80 

37,000 

0.198 

120,600 

9.90 

8,000 

0.018 

26,076 

0.90 

38,000 

0.21O 

123,860 

10.50 

9,000 

0.019 

29,335 

0-95 

39,000 

O.221 

127,119 

".05 

10,000 

O.02I 

32,595 

1.05 

40,000 

0.239 

130.379 

"•95 

12,000 

O.028 

39,  "4 

1.40 

41.000 

0.253 

133,638 

12.65 

14,000 

0.037 

45,633 

1.85 

41,500 

0.267 

135,268 

13-35 

16,000 
18,000 
20,000 

22,000 

0.046 
0.056 
O.o66 
0.078 

52,152 
58,671 
65,190 

2.30 

2.80 
3.30 
3.90 

42,000 
42^500 
just  as 
Fracture 

O.272 

beam  rose, 
diagonally  a 

136,898 
138,528 

:ross  the  mic 

13.60 
Broke 

die  of  the 

24,000 

0.000 

78^228 

4.50 

specimen. 

STRENGTH  OF  BRASSES.  399 

TABLE  LXXV. 

RECORD   OF  TESTS   BY   TRANSVERSE   STRESS. 

Alloys  of  copper  and  zinc.     Dimensions:  Length,  1=  22"  ;  breadth,  6=  l" 
(2.54  cm.) ;  depth,  d=  i"  (2.54  cm.). 

BAR  NO.   4. 

COMPOSITION.— Original  mixture  :  Cu,  80;  Zn,  20.    Analysis:  Cu,  81.91 ;  Zn,  17.99. 


LOAD. 

DEFLECTION. 

SBT. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 

10 
20 

£ 

130 

160 

200 

3 

% 
% 

400 

3 
400 

Inch. 
0.0042 
0.0080 
0.0124 
0.0206 
0.0296 

0.0363 
0.0449 

-  Inch. 

Pounds. 
49o 
440 
460 
480 
Soo 
520 
540 
56o 
580 
600 
620 
Bent  dow 
Breaking 

Modulus 

Inches. 
0.4414 
0.5885 
0.7520 
0.959° 
1.1763 
1.3463 
i.6.'63 
1.86 

2.22 
2.62 
3-2? 

n  without 
load,  P  = 

:>f  rupture, 

Inches. 

9,030,560' 
10,708,667 
11,349,217 
12,339,278 
12,469,814 

1,189,949 

0.0056 

Beam  sinks 
slowly. 

0.2445 

0.0544 
0.0692 

0.3352 

12,350,618 
«,327,32o 

9,141,138 
6,074,807 
3,405,686 

breaking.   E 
620  pounds. 

R      3/V 
R—*b&- 

641,107 

ar  removed. 
21,193- 

BAR  NO.   5. 

COMPOSITION.— Original  mixture :  Cu,  75 ;  Zn,  25.    Analysis ;  Cu,  76.65  ;  Zn,  23.28. 


10 
20 

£ 

120 

160 

200 

3 
240 
280 
320 

360 
4°o 

3 
400 

0.0024 
0.0066 

0.01II 

0.0204 
0.0288 
0.0354 
0-0439 

0.0514 
0.0620 
0.0772 

0.1094 

0.2010 

4f 
460 
480 
500 
520 
540 

s? 

e 

6?o 
640 

10 

Bent  with 
Breaking 

Modulus 

0.4110 

0.5396 
0.6989 
0.9489 

l.IO 

!:£ 

1:3 

2.64 

3-39 

out  bireaki 
load,/>=< 

if  rupture, 

0.0059 

Beam  sinks 
slowly. 

10,347,419 
11,260,425 
11,964,201 
12,978,117 
13,081,593 

'...'. 

1,513,020 

t3,407,355 
12,967,651 
11,902,213 

9,448,876 
5,714,246 

755,634 

3  .  19               
ng.    Removed  bar. 
540  pounds. 

*=-^  =  "'*5- 

0.2129 

4OO  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE  LXXV .— Continued. 

BAR   NO.    6. 

COMPOSITION.— Original  mixture :  Cu,  70 ;  Zn,  30.    Analysis :  Cu,  71.20 ;  Zn,  28.54. 


. 

*,   • 

. 

&H           * 

o 

o  £ 

o 

°  H 

H 

£fl  n 

H 

D  D 

LOAD. 

u 
w 

SET. 

p  & 

LOAD. 

U 

SET. 

Bfe 

u, 
w 

Q  < 

0  J 

to 

14 

Q 

S  w 

° 

S  w 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inches. 

Inches. 

IO 

0006? 

0.6832 

' 

40 
80 

O.OI72 

6,691,260 

560 

i  .  1092 

1  20 
160 

0.0334 
O.O4O6 

0,337,393 
1,338,883 

10 

580 
600 

1.1467 

1.3462 
1.55 

1,113,771 



i.  So 

"   '  -R' 

0.0052 

*  "QA  "    V" 

240 
280 

o  0680 



660 

2.45 

320 
360 
400 

3 
440 

0.0794 
0.0957 
o.  1268 

o  2147 

Beam  sinks 
0.0408 

",595,933 
10,823,479 
9,076,471 

680 
700 
Bent  will 
Breaking 

2.80 
3-30 
lout  break 
load,  P  = 

ng.    Remov 
700  pounds. 

610,324 
ed  bar. 

480 

0.4258 

Modulus  of  rupture,  R  =  ^rj2  =  24,468. 

500 

0.5396 



2,660,088 

BAR  NO.   7. 

COMPOSITION.— Original  mixture  :  Cu,  65  ;  Zn,  35.    Analysis  :  Cu,  66.27  ;  Zn,  33.50. 


IO 
20 
40 
80 
120 

160 

200 

3 

240 

280 

320 

360 

400 
440 

480 

520 
1^ 

600 

0.0028 
0,0058 
0.0124 
0.0233 
0.0317 
0.0384 
0.0466 

0.0546 
0.0642 
0.0728 
0.0836 

0.0948 

O.IIIO 

0.1454 
0.2128 
0.4680 
0-5958 

6,1 

640 
660 
680 
700 
720 
740 
760 
780 

Repeate 
780 
800 

820 

IO 

Bent  wi 
Bar  rem 
Breakin 

Modulu 

0.6734 
0.8^36 
1.0268 
1.2058 
1.41 
1-59 
1.79 
2.04 

d.2'34 

2.84 
3-34 
3-84 

hout  breal 
oved. 
er  load.  P  = 

3  of  ruptur 

0.5538 



0.0033 

O.OIT2 

Beam  sinks 
slowly. 

9,168,783 

9,759,049 
10,759,827 
11,843,014 
12,198,812 



1,411,082 

12,493,727 
12,396,423 
12,493,727 
12,239,668 
11,992,925 

11,226,865 



680,796 

.     3-54                
cmg. 

=  820  pounds. 
e'*-^-28'«9. 

6,9M,525 



2,862,360 

STRENGTH  OF  BRASSES. 


401 


TABLE   LXXV.— Continued. 


BAR  NO.   8. 


COMPOSITION.— Original  mixture  :  Cu,  60  ;  Zn,  40.    Analysis  :  Cu,  60.54 ;  Zn,  38.65. 


LOAD. 

'§ 

M 

Q 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
40 
80 

120 

160 

200 
10 
240 
280 
320 
360 
400 
10 
400 

Left  unde 
sistance 

10 

440 
480 
520 

& 

10 
640 
720 
800 

10 

Inch. 
o  .  0203 
0.0291 
0.0380 
0.0447 
°-°534 

Inch. 

0.0105 

5,488,205 
7,835,438 
8,795,568 
9,969,625 
10,431,698 

10,678,327 
10,816,556 
10,869,170 
11,067,272 

Pounds. 
800 
Resistanc 
10 
840 
880 
900 
920 

$ 

980 

1,000 
1,100 

Resistanc 
Resistanc 
Resistanc 
pounds. 
1,130 

Randowr 

1     maximu 
pounds. 
•  Bent  with 
Breaking 

Modulus  < 

Inches. 
0.5090 
e  decreasec 

0.5275 
0.9685 
0.9885 
1.04 
1.26 
1-33 
i  53 

I.fc2 
2.67 

2  decreasec 
;  decreased 
;  decrease 

2.72 
2.75 
pressure  s 
n  resistan 

out  breaki 
load,  P  = 

>f  rupture, 

Inches. 

[  in  i  hour  to 
0.3224 

782  pounds. 

2,535.900 

0.0626 
0.0721 
0.0820 
0.0906 

O.IOOO 
O.  IO2O 

r  strain  18 
to  deflectu 

0.0135 

1,719,298 

in  30  sec.  to  1,026  pounds, 
in  i  m.  to  1,020  pounds, 
i  in  17  hr.  30  m.  to  990 

hours  ;  deflection  and  Te- 
rn unchanged. 

0.1IOI 

0.1193 
0.1290 
0.1425 
0.1585 

0.1747 
0.2555 
0.5021 

11,130,936 
11,206,425 
11,227,419 
10,945,596 
io,543i585 

crew  about  i 
ce  to  rapid 

ng- 
1,140  pounds 

R       3Pl 

nch  further; 
motion  1,160 

=  38,968. 

0.0283 
0.3060 

10,203,600 
7,848,884 
4,437,784 

~  zbd* 

BAR  NO.  9. 

COMPOSITION.  —  Original  mixture:  Cu,  55  ;  Zn,  45.    Analysis:  Cu,  55.15  ;  Zn,  44.44. 

20 

£ 

120 
1  60 
200 
10 
240 
280 
320 
300 
400 
10 

$ 

520 

a 

10 

640 
680 

700 
720 
800 

10 

800 

0.0080 
0.0148 
0.0285 

0.0398 

o  0505 
0.0612 

0.0800 

0.0900 
0.1004 

0.1110 

0.1317 

860 
880 
900 
920 
940 
960 
Resistanc 
Resistanc 
Resistanc 

10 

920 
940 
960 
980 

1,000 
I,O2O 
1,100 

1,  160 
Crackling 
1,180 

1,200 

Breaking 
Modulus  < 

.0364 
.1250 
•1953 
.2722 

.3423 
.4647 
e  decrease 
e  decrease 
e  decrease 

•  4785 
•  5175 

:&S 

:??5 

.24 
.65 
sound  hea 
2.79 
Bar  ben 
from  u 
load,  /»  = 

>f  rupture, 



0.0080 

7,888,340 
8,194,687 
8,800,055     i 
9,247,321 
9,538,189    | 

8,756,005 
9,080,354 
9,302,585 
9,466,607 
8,864,649 

2,197,622 

3  in  5  min.  to 
i  in  20  min.  t< 
i  in  16  hr.  to 
1.2233 

950  pounds. 
5  942  pounds. 
916  pounds. 



0.1496 
0.1790 
0.247 
0.2645 
0.3306 

0.3951 

0.5060 

0.5315 
0.5833 
0.8367 

o!858i 

0.1663 

8,584,370    | 
7,826,643    \ 
7,069,010 

5,297,071 



1,653,646 



1,433,283 

jrd  from  bar. 

.  ar.d  supports  slid  out 
ider  it. 
i  ,200  pounds. 

*-i£-«M*. 



4,839,294 

0.6250 

2,790,663    i 

i 

4O2  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE    LXXV.— Continued. 

BAR    NO.     10. 

COMPOSITION. — Original  mixture  :  Cu,  50  ;  Zn,  50.    Analysis  :  Cu,  49.66  ;  Zn,  50.14. 


tb 

h 

°  > 

H 

°£ 

LOAD. 

DEFLEC- 
TION. 

SET. 

en  CJ 

li 

LOAD. 

DEFLEC- 
TION. 

SET. 

32 

gg 

33 

is 

8" 

iw 

Pounds. 

Inch. 

.  Inch. 

Pounds. 

Inches. 

Inches. 

20 

0.0065 

680 

0.5990 

40 

O.OIIO 

10,711,665 

720 

0.6700 

3>l65,537 

80 

0.0219 

10,760,578 

760 

0.7647 



120 

0.0330 



10,711,665  i 

800 

0.6813 

2,704,656 

160 

O    O42O 

10  986  324    | 

IO 

o  6600 

2OO 

A  slight  cr 
strain  re 

u.u^y 

0.0509 
acklmg  so 
mained  or 

und  was  hea 
i  the  bar,  tf 

11,574491 

rd  while  the 
ie  deflection 

800 
840 

880 

0^8713 
0  9493 
1.0613 

v*  wuyy 

being  he 

10 

200 

Id  constan 
0.0025 
0.0509 

L 
Beam  sinks 

920 
940 

cracks  we. 

i  .  1690 
Onapplyir 
re   heard. 

ig  the  stress  s 
but  there  wz 

everal  si  ight 
is  no  visible 

240 
280 

0.0623 
0.0773 

slowly. 

11,347,832 
10,670,093 

appearance  of  breaking.    The  resistance  sud- 
denly decreased,  and  on  balancing  the  scale 
beam  was  found  to  be  580  pounds. 

O  .  I  O  X) 

ego 

360 

°-I337 

..... 

7,931,600 

500 
10 

A  •  ^3/V 

1.1195 

400 

0.1736 

6,787,347 

Applied    stress    again,   and    the    resistance 

10 

440 
480 

520 

0.2220 
0.2752 
0.3291 

0.0816 

^'  5,838,341  : 

4>654,415 

reached  500  pounds  when  the  bar  broke. 
The  crackling  sound  noticed  first  at  200  pounds 
continued  throughout  the  test  while  the  bar 
was  strained,  even  when  the  deflection  was 



560 

0.3909 

held  constant  for  several  minutes. 

600 

0.4568 

3,869,144 

Breaking  load,  P  =  940  pounds. 

10 

640 

0.5182 

0.3165 

Modulus  of  rupture,  R  =  —  ~j~r^  —  331467. 

ALLOYS  OF  COPPER  AND   ZINC. 


BAR  NO.   32. 


Resistanc 
3 
751 
800 
820 
840 
860 
880 
900 
920 

% 

e  decrease 

0.3364 
0.3490 
0.3583 
0-379° 
0.3948 
0.4145 

0-4H3 
0.4518 
0.4669 
0.4905 

d  in  22  hrs.  to 
0.1638 

751  pounds. 

980 

1,000 
I,C2O 
I  040 

0.5122 
0.5302 

0.5444 
o.  S7i8 

'.'.':.'.'. 

5,718,889 

:::::: 



1,080         0.6140            5,333*432 
1,100       Broke  in  middle  just  as  beam  rose. 
Breaking  load,  P=  1,100  pounds. 

Modulus  of  rupture,  R  =  -  7-=  =  40,189. 
2  od* 
The  crackling  sound  noted  at  520  pounds  con- 
tinued till  the  end  of  the  test,  even  when  the  de- 
flection was  held  constant  for  several  minutes. 



6,283,536 

STRENGTH  OF  BRA 


TABLE   LXXV.— -Continued 

BAR  NO.   33. 

COMPOSITION.— Original  mixture  :   Cu,  42.5 ;  Zn,  57.5.    Analysis:   01,43.36;  Zn,  56.22;  Pb, 


LOAD. 

g 

e 

SET. 

\\ 

LOAD. 

1 

SET. 

I 

3 

K 
H 
Q 

If 

2  W 

j 
E 

S 

il 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

IO 

0.0030 

360 

^o^ 

20 

C 

0.0164 
0.0279 



5,  95°,  *  34 
5,246,355 

3 

7  9 

0.0115 

12,628,285 

0.0850 

1  20 

°-0354 

8,246,381 

480 

0.0909 

...... 

12,882,137 

160 

200 

3 

0.0421 
0.0497 

0.0063 

9,271,468 
9,817,123 

520 
540 
Breaking 

0.0982 
Broke  jus 
load,  />«= 

t  as  beam  n> 
540  pounds. 

12,918,211 
se. 

240 
280 

0.0556 
0.0614 

10,530,451 
11,125,005 

Modulus  of  rupture,  /?=  —  7—  —  17,691. 

320 

0.0672 

11,616,928 

BAR   NO.   39. 

COMPOSITION.— Original  mixture:  Cu,  12.5;  Zn,  87.5.    Analysis:  Cu,  12.12;  Zn,  86.67; 

Pb,  1.22. 


TO 

600 

2O 

0.0056 

o 

0.01.18 

40 

0.0128 

8,982,413 

Resistance  increased  in  10  minutes   to  ro 

80 

0.0234 



9,826,913 

pounds. 

12O 

10,484,031 

o  0114 

160 

200 

0.0430 
0.0526 



i«,695,338 
10,929,173 

640 
680 

0.1663 
0.1796 

11,061,926 
10,882,925 

240 

0.0641 

10,762,079 

0.2116 



10,323,831 

280 

800 

o  2261 

320 

0.0818 

11,244,489 

3 

0.0378 

360 

0.0921 

Beam  sinks 

",235,332 

840 

0.2450 

9,8S4,99X 

slowly. 

880 

0.2624 

400 

0.1016 

11,316,427 

920 

0.2856 

3 

0.1115 
0.1216 

0.0064 

11,342.857 
11,346,204 

960 

I.OOO 

Breaking 

0.3124 

Broke  jus 
load,  P^ 

t  as  beam  ro 
i,ooo  pounds 

8,832,898 
se. 

. 

520 
56o 

o.  1316 
0.1421 

:::::: 

",359,423 
"»327<574 

Modulus  of  rupture,  R  =  ~r^  *^  35,026 

BAR   NO.  41. 

COMPOSITION.— Original  mixture :  Cu,  2.5  ;  Zn,  97.5.    Analysis :  Cu.  2.45  ;  Zn,  96.43 ;  Pb,  1.05. 


440 

o  1895 

40 

0.0154 

8,117,624 

480 

0.2225 



6,588,717 

80 

O.02<?5 

. 

9.581,630 

520 

0.2596 



120 

160 

0.0362 
0.0486 

• 

10,124,235 
10,054,796 

569 

foo 

0-3137 
0.3950 

5,452,091 
4,639,208 

o  881  06-1 

3 
240 
280 

0.0764 
0.0932 

o  0051 

630 

0.4097 
Crack  ap] 
resistam 

reared  in  bottom  of  bar  ; 
e  decreased  rapidly,  and 

Beam  sinks 

9,175,542 

slowly. 

bar  broke. 

320 

0.1124 

8,695,074 

Breaking  load,  P=  630  pounds. 

360 
400 

0.1601 

8,132,338 
7,630,593 

Modulus  of  rupture,  R  =  —  -  -r  =  23,137. 
2  ba* 

3 



0.0498 

404  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

237.  The  Method  of  Variation  of  Resistance  with  dis- 
tortion is  illustrated  by  strain-diagrams,  several  of  which,  as 
obtained  by  tests  in  tension,  are  given  in  Figure  17.  TLese 
strain-diagrams  are  produced,  in  this  case,  by  plotting  the 
record  of  test,  making  the  ordinates  of  the  curve  proportional 
to  the  load  and  the  abscissas  variable  with  the  extension.  In 


LBS  PER  HO  !»!. 
60:000 


FIG.  17.— STRAIN-DIAGRAMS  OF  BRASSES. 
TESTS  DY  TENSILE  STRESS. 


.01     .02    .03     .04     .05     .00    .07    .03     .09     .10     .11     .12    .13     U.    .13     .10     .17     .18     .10     .20     .21     .23     .2£ 
ELONGATION  IN  PARTS  OF  ORIGINAL  L/NGTH. 

preparing  the  test-pieces,  the  yellow  alloys,  Nos.  I  to  10,  con- 
taining less  than  0.55  zinc,  were  easily  turned  in  the  lathe. 
The  white  alloys,  Nos.  12  to  15,  0.60  to  0.70  zinc,  could  not 
be  turned  as  they  were  too  brittle  to  be  worked  ;  these  were 
tested  in  the  bar,  unturned.  The  blue-gray  alloys,  Nos.  16  to 
21,  containing  over  75  per  cent,  zinc,  were  more  easily  cut 
than  the  first  class  and  were  tested  in  standard  form  and 
size. 


STRENGTH  OF  BRASSES. 


405 


Studying  these  diagrams,  it  is  seen  that,  in  some  cases, 
there  appears  the  semblance  of  an  elastic  limit  at  not  far 
from  one-half  the  maximum  resistance.  This  is  most  easily 
seen  in  the  diagrams  of  Nos.  4  to  8.  The  tenacity  varies 
enormously,  as,  for  example,  between  Nos.  8  or  9  and  21. 


Pounds 


FIG.  1 8. — STRAIN-DIAGRAMS  OF  BRASSES. 

Te?ts  By  Transverse  Stress 


.20    .40    .iiO    .80   1.00  1.20  1.40  1.60  1.80  2.00  2.20  2.40  2.60  2.80  3.00  3.20  3.40  3.60  3^0  4.00  4.20  4.40  4.60  4.80 
Deflection  in  Inches 

The  ductility  is  correspondingly  variable,  as  illustrated  by 
the  same  cases.  The  elastic  resilience  is  evidently  greatest 
with  brittle  alloys,  as  Nos.  1 1  A,  1 1  B ;  but  the  total  re- 
silience, as  measured  by  the  area  covered  by  the  curves,  is 
seen  to  be  enormously  greater  in  the  strong  and  ductile 
alloys,  of  which  Nos.  8  and  9  (Muntz  metal)  containing  40  and 
45  per  cent,  zinc  are  examples.  Nos.  8,  9  and  10,  which  con- 
tain from  40  to  50  per  cent,  zinc,  are  obviously  by  far  the 


406  MATERIALS  OF  ENGINEERING— NON FERROUS  METALS. 

best  compositions  for  general  use,  and    the  next  best  class 
contains  less  zinc,  as  Nos.  4  to  7  (zinc,  20  to  35). 

238.  Strain-Diagrams  obtained  by  Transverse  Stress, 
Figure  18,  are  illustrative  of  the  same  facts  as  were  exhibited 
by  tests  in  tension.  These  are  another  set  of  bars  similarly 
graded  from  copper,  100,  to  zinc,  100.  Here  again  a  Muntz 
metal,  No.  30  (zinc,  40),  is  by  far  the  best.  Nos.  29  to  32, 
form  a  valuable  group  (zinc,  37.5  to  50),  and  the  lower  num- 

FIG.  19. — COMPARISON  OF  RESISTANCES. 


COPPER95     90 


SO     75      70      65     60     55     50     45      40     35     3D 
Composition  by  Analysis 


15    10     (ZINC 


bers,  containing  less  zinc,  stand  next  in  order.  The  smooth- 
ness of  these  curves  is  remarkable. 

No  definite  elastic  limits  are  found  here,  although  some 
alloys,  as  Nos.  22-28,  present  indications  of  one  nearly  as  well 
defined  as  is  sometimes  the  case  with  the  best  iron. 

239.  Comparisons  of  Resistances,  as  determined  by  the 
several  methods  of  test,  are  made  by  plotting  the  curves  of 
resistance  side  by  side,  as  in  Figure  19.  No  direct  relation  is 
known  to  exist  among  these  variations  of  load  and  of  distor- 
tion, but  a  close  correspondence  of  general  form  is  seen  in  the 
diagrams. 

The  curves  are  so  irregular  that  it  is  evident  that  further 


STRENGTH  OF  BRASSES.  407 

investigation  will  be  needed  to  ascertain  their  exact  form,  as 
determined  by  composition  and  unaltered  by  physical  and 
accidental  conditions.  The  positions  of  the  maximum  and 
the  minimum  are  very  nearly  the  same,  as  indicated  by  all 
forms  of  test,  and  may  be  taken,  for  practical  purposes,  as  at 
zinc,  35  to  40,  and  at  zinc,  60  to  65,  respectively.  All  methods 
of  test  concur  in  showing  that  the  valuable  alloys  for  the 
ordinary  work  of  the  engineer  lie  on  the  copper  side  of  the 
maximum,  where  alloys  are  found  which  are  tough  as  well  as 
strong.  Those  lying  on  the  zinc  side  of  the  minimum,  and 
near  the  composition,  copper,  15  to  20,  zinc,  85  to  80,  may 
prove  valuable  as  bearing  metals  and  for  castings  or  worked 
parts  not  required  to  be  of  great  strength  ;  their  malleability 
constitutes  their  prominent  good  quality. 

The  curves  of  resistances  to  various  kinds  of  stress  show 
that  they  have  a  close  relation  depending  upon  the  composi- 
tion, in  a  portion  of  the  series,  but  exhibiting  a  very  different 
law  in  other  portions. 

The  alloys  between  17.5  and  32.5  per  cent,  zinc  by  origi- 
nal mixture,  or  between  16.98  and  30.06  per  cent,  zinc  by 
analysis,  show  a  remarkable  similarity  in  all  properties.  They 
have  all  nearly  the  same  strength,  and  nearly  the  same  duc- 
tility, the  latter  decreasing  slightly  as  the  percentage  of  zinc 
increases.  They  are  similar  in  color  and  appearance,  so  that 
one  could  scarcely  be  distinguished  from  the  other.  Their 
moduli  of  elasticity  are  nearly  the  same.  The  moduli  of 
rupture  by  transverse  stress  in  this  group  varied  from  21,193 
to  26,930  pounds  per  square  inch  (1,490  to  1,893  kilogs.  per 
sq.  cm.),  these  moduli  being  calculated  from  the  loads  which 
caused  deflections  of  $%  inches  (9  cm.),  as  all  of  the  bars  bent 
without  breaking.  The  mean  tensile  strength  of  the  two 
pieces  from  each  bar  varied  from  28,120  to  35,630  pounds  per 
square  inch  (1,977  to  2,505  kilogs.  per  sq.  cm.),  the  lowest 
figure  being  exceptional,  and  the  piece  possibly  slightly  de- 
fective, as  the  next  higher  figure  was  30,510  pounds  (2,144 
kilogs.  per  sq.  in  ). 

All  bars  which  contained  less  than  15  per  cent,  zinc  by 
mixture,  or  less  than  11.06  per  cent,  zinc  by  analysis,  were 


408   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

defective,  and  their  resistances  were  accordingly  lower  than 
would  be  observed  with  sound  castings.  A  few  pieces  of  this 
group  gave  higher  results  than  the  average,  and  these  may 
be  taken  as  probably  nearly  the  results  which  would  be  given 
if  the  bars  had  been  sound  throughout. 

Between  the  compositions  containing  32.5  and  37.5  per 
cent,  zinc  by  mixture,  or  30.06  and  36.36  per  cent,  zinc  by 
analysis,  occurs  a  rapid  increase  of  strength.  The  latter 
alloy  (63.44  copper,  36.36  zinc),  had  a  modulus  of  rupture 
of  43,216  pounds  (3,038  kilogs.  on  the  sq.  cm.),  and  a  mean 
tenacity  of  48,300  pounds  per  square  inch  (3,395  kilogs.  per 
sq.  cm.). 

Between  the  compositions  containing  37.5  and  55  percent, 
zinc  by  mixture,  or  36.36  and  52.28  per  cent,  zinc  by  analysis, 
is  another  group  of  alloys,  which  contains  that  of  maximum 
strength  by  transverse,  tensile,  and  torsional  tests,  but  not  by 
compressive  test,  and  higher  than  that  of  the  first  group. 
The  moduli  of  rupture  vary  from  33,467  to  63,304  pounds 
(2,353  to  445°  kilogs.  per  sq.  cm.),  the  mean  tenacity  from 
two-thirds  to  four-fifths  as  much.  The  figures  decrease  as 
the  proportion  of  zinc  increases  beyond  that  which  is  con- 
tained in  the  alloy  of  maximum  strength  (58.49  copper, 
41.10  zinc).  The  curves  of  test  indicate  that  this  composition 
is  nearly  that  of  maximum  strength,  and  probably  within  2  per 
cent,  of  the  actual  maximum.  The  alloy  of  maximum  strength 
contains  about  41  per  cent,  of  zinc.  The  compressive  strength 
of  this  group  bears  no  relation  to  tensile,  transverse,  or  torsional 
strength,  as  it  increases  regularly  with  the  increase  of  zinc  ;  and 
the  maximum  compressive  strength  of  all  alloys  of  copper  and 
zinc  is  probably  reached  at  an  alloy  containing  more  than  55 
per  cent  of  zinc.  The  ductility  of  this  group  has  no  relation 
to  strength,  and  always  decreases  as  the  proportion  of  zinc 
increases. 

The  alloys  containing  less  than  55  per  cent,  of  zinc  by 
mixture  (52.28  zinc  by  analysis),  are  the  yellow  metals  or  use- 
ful alloys. 

Between  the  compositions  containing  55  and  60  per  cent, 
zinc  by  mixture  (or  52.28  and  58.12  zinc  by  analysis)  there  is 


STRENGTH  OF  BRASSES.  409 

a  rapid  decrease  of  strength  as  well  as  a  rapid  decrease  of 
ductility. 

Between  the  compositions  containing  60  and  70  per  cent, 
zinc  by  mixture  (or  58.12  and  66.23  Per  cent,  by  analysis) 
there  is  some  uniformity  of  strength,  these  being  the  second 
class,  silver-white,  brittle  alloys.  The  moduli  of  rupture  of 
this  group,  and  the  tenacity  are  low. 

Between  the  compositions  containing  70  per  cent,  zinc  by 
mixture  and  pure  zinc,  comprising  the  bluish-gray  alloys,  the 
curves  of  resistances  gradually  fall. 

240.  Resilience. — The  resilience  of  pieces  containing  less 
than  15  per  cent,  of  zinc  are  uncertain  in  consequence  of  their 
being  defective.     Two  torsion  pieces  within  this  limit  give  the 
maximum  resiliences  of  896.69  and  881.59  foot-pounds,  these 
pieces  being  also  the  most  ductile  under  torsional  test.     From 
the  latter  of  these  figures  there  is  a  rapid  and  comparatively 
regular  decrease  of  total  resilience  by  torsion  to  alloy  38.46 
copper,  61.05  zinc,  only  about  ov^o^th  °f  the  maximum.    The 
resiliences  by  transverse  test,  on  the  contrary,  increase  from 
the  defective  bars  to  the  bar  of  maximum  strength,  58.49  cop- 
per, 41.10  zinc,  with  considerable  regularity,  as  the  strength 
increases,  and  then  as  the  bars  become  of  such  low  ductility 
as  to  break,  the  resilience  decreases,  and  the  curve  takes  nearly 
the  same  form  as  the  curve  of  torsional  resilience  to  the  end 
of  the  series. 

From  alloy  41.30  copper,  58.12  zinc,  to  14.19  copper,  85.10 
zinc,  the  resiliences  are  small,  corresponding  with  the  combi- 
nation of  low  strength  and  low  ductility.  At  alloy  7.20  cop- 
per, 92.07  zinc,  there  is  a  second  maximum  of  resilience,  the 
very  large  increase  of  strength  of  the  alloy  over  those  of  mini- 
mum strength  contributing  to  give  this  alloy  more  resilience 
than  cast  zinc,  although  the  latter  has  much  the  greater  duc- 
tility. 

241.  Limit  of  Elasticity. — In  the  table  of  results  of  tests, 
figures  are  given  representing  the  transverse  load  at  the  ap- 
parent elastic  limit  and  corresponding  modulusf  R  =  —  T-^)« 

The  relation  between  the  elastic  limit  and  ultimate  strength 


410  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


appears  to  vary  considerably.  The  percentage  ratios  by  trans- 
verse tests  appear  to  be  greater  than  those  by  the  other 
methods  of  test. 

In  the  more  ductile  alloys,  containing  less  than  50  per 
cent,  of  zinc,  the  elastic  limit  is  generally  from  20  to  50  per 
cent,  of  the  ultimate  strength  ;  as  the  percentage  of  zinc  in- 
creases beyond  50  per  cent.,  and  the  alloys  become  more  brittle, 

FIG.  20. — MODULI  OF  ELASTICITY  AND  SPECIFIC  GRAVITY. 

(From  Transverse  Tps-ts) 


16.000.000 

a  ooo  ooo 

! 

--  I    | 

m  -   g  — 

W^- 

-jyj- 

I-  ---_- 
1 

L  : 

12.000.000 
10.000.000 
C  00 

^x,^-> 

^r 

4::: 

~^^- 

^-—  — 

_—  ^-- 

^^ 

^-^ 

^ 

v,- 

--  -; 

ipEiqib^frfe 

~\ 

v^ 

N^ 

880 

igl 

8.60 

""**"•-  --^ 

— 

8.10 

8.20 
8.00 
7.80 
ff.60 

- 

>^ 

^ 

:••• 

•  •  c 

•"-S^ 

g 

- 

n 

\ 

_  -i 

X 

m 

\ 

mm 

7.40 

n 

: 

7.20 

•'1 

::.:.::. 

x 

9.10 
COPP 

- 

s< 

""-*- 

- 

NO 

ER'JO     W      86      80      75      70      65      00      55      50      45      40      35      W      25      20      15      10 
Composition  by  Analysis 

5  Z 

the  elastic  limit  is  not  clearly  defined,  but  appears  to  approach 
more  nearly  to  the  ultimate  strength  in  tensile  than  in  other 
tests. 

In  brittle  alloys,  containing  from  56.22  to  85.10  per  cent, 
zinc,  the  elastic  limit  is  not  reached  until  fracture  takes  place. 

From  85.10  per  cent,  to  pure  zinc,  the  ratio  decreases  by 
transverse  tests,  while  in  tensile  tests  the  ratio  apparently  re- 
mains at  100  per  cent,  till  96.43  per  cent,  zinc  is  reached.  In 
torsion  tests  the  elastic  limit  begins  to  be  less  than  the  ulti- 
mate strength  after  86.67  per  cent,  zinc,  the  ratio  decreasing 
as  the  percentage  of  zinc  increases. 


S  TRENG  TH  OF  BRA  SSES.  4 1 1 

242.  The  Moduli  of  Elasticity  of  the  copper-zinc  alloys 
are  variable  according  to  a  law  which  is  probably  nearly  repre- 
sented by  the  upper  curve  in  Figure  20.  The  modulus  for 
copper  is  low,  and  the  figure  gradually  rises  as  zinc  is  added, 
until  passing  zinc  25,  it  falls  again,  passing  a  mmimum  at 
about  zinc  50,  and  a  second  maximum  not  far  from  zinc  75, 
and  falls  off  rapidly  to  a  minimum  at  pure  zinc.  Further  in- 
vestigation is  needed  to  determine  to  what  extent  these  fluct- 
uations are  due  to  chemical  and  what  to  physical  causes. 
The  Author  is  inclined  to  believe  that  sound  castings  contain- 
ing large  amounts  of  copper  would  give  higher  figures. 

The  moduli  of  elasticity  given  in  the  above  table  were  se- 
lected from  the  records  of  test  by  transverse  stress. 

The  average  figure  for  the  alloys  is  nearly  13,000,000 
(913,900  kilogs.  per  sq.  cm.).  The  variation  of  the  figures  of 
bars  of  different  composition  does  not  have  any  relation  to 
density,  strength,  or  other  mechanical  property,  but  follows  a 
law  of  its  own. 

There  appears  to  be  an  increase  of  the  modulus  with  in- 
crease of  percentage  of  zinc  up  to  the  alloy  containing  16.98 
per  cent,  of  zinc.  It  then  appears  to  be  nearly  uniform  from 
16.98  to  36.36  zinc.  From  36.36  zinc  to  44.44  zinc  there  is  a 
regular  and  rapid  decrease,  and  from  44.44  zinc  to  52.28  zinc 
there  is  a  regular  and  rapid  increase.  This  break,  almost  a 
cusp  in  what  might  otherwise  be  a  regular  curve,  is  indicated 
by  all  observations  between  the  limits  of  36.36  and  52.28  zinc. 

The  increase  in  the  modulus  continues  from  the  alloy  con- 
taining 52.28  per  cent,  zinc  to  that  containing  66.23  Per  cent, 
zinc.  The  latter  alloy  gives  the  maximum  modulus  of  the 
series.  From  this  point  there  is  a  rapid  decrease  to  pure 
zinc,  which  gives  the  minimum  modulus. 

The  bars  which  make  this  break  include  the  strongest  bars 
of  the  series,  and  those  which  exhibited  the  phenomena  of 
irregularity  in  increase  of  deflection  under  transverse  stress 
and  of  emitting  the  crackling  sound  (cry  of  tin)  when  held  at 
a  constant  deflection.  They  also  include  metals  of  a  wide 
range  of  ductility  r.nd  hardness,  and  of  a  structure  varying 
from  fibrous  to  coarsely  granular. 


412  MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS. 


243.  The  Curve  of  Specific  Gravities  is  presented  on  the 
lower  part  of  the  same  figure,  under  that  of  the  moduli  of 
elasticity.  This  curve  is  not  as  smooth  as  that'given  for  the 
bronzes,  and  it  may  ultimately  be  found  necessary  to  revise  it 
to  some  extent.  The  general  method  of  variation  is  very 
similar  to  that  given  for  copper-tin  alloys.  Its  equation  may 
be  taken  as  approximately, 

D  —  7  +  0.019  C, 

in  which  D  is  the  specific  gravity  and  C  the  percentage  of 
copper.     It  is  not,  however,  a  straight  line,  but  has  probably 

FIG.  21. — COMPARATIVE  DUCTILITY. 


TRANSVERSE  - 
DEFLECTION  i  ^ 

3.00 


S.7E 
2.50& 


2.00 


.CO  0.12 
0.40  0.08 
0.20  0.01 


COPPER95     iX)      85     80      75      70     65      60      55      SO     45      40      S5 
Composition  by  Analysis 


20      15     10      5  ZINC 


the  same  smooth  and  moderate  curvature  observed  in  that 
given  for  the  bronzes.  A  smooth  curve  osculating  that  here 
given  on  the  upper  side  of  the  latter,  is  perhaps  the  true  curve. 
It  would  terminate  at  very  nearly  or  quite  S.  G.  =  9  on  the 
copper  side,  and  at  S.  G.  =  7.15  at  the  zinc  end. 

244.  Comparisons  of  Ductility  of  the  copper-zinc  alloys 

are  graphically  exhibited  in  the  above  figure,  as  determined 

by  the  several  methods  of  test.    It  is  seen  that  it  varies  in  the 

opposite  direction  to  the  change  of  strength  with  variation  of 

Composition  and  to  be  different  in  its  distribution  from  that 


STRENGTH  OF  BRASSES.  413 

observed  in  the  copper-tin  alloys.  All  bars  containing  be- 
tween 16.98  and  38.65  per  cent,  zinc  have  a  high  degree  of 
ductility,  the  mean  extension  of  the  two  pieces  of  each  bar 
varying  from  20.67  to  38.5  per  cent.  With  the  increase  of 
zinc  beyond  38.65  per  cent,  the  ductility  decreases  till  52.28 
per  cent,  zinc  is  reached,  the  mean  extension  of  the  alloy  of 
this  composition  being  only  0.79  per  cent.,  or  but  little  more 
than  one-fiftieth  of  the  maximum.  From  52.28  to  70.17  per 
cent,  zinc,  the  elongations  could  not  be  determined,  most  of 
the  pieces  being  tested  in  their  original  rectangular  sections. 
Their  extensions  were,  without  doubt,  much  less  than  0.79 
per  cent.,  as  the  test-pieces  appeared  nearly  as  brittle  as  glass. 
From  77.43  to  96.43  per  cent,  zinc  the  elongations  very  slowly 
increase,  that, of  the  former  composition  being  only  0.12  per 
cent.,  and  that  of  the  latter  0.88  per  cent. 

The  form  of  the  curve  and  one  test  showing  an  exception- 
ally high  ductility  of  607  degrees  angle  of  torsion,  or  an  ex- 
tension of  2.5011  (No.  3,  89.80  copper,  10.06  zinc),  indicate 
that  the  maximum  ductility  of  the  alloys  of  copper  and  zinc 
is  found  among  alloys  containing  small  quantities  of  zinc. 
From  16.98  to  61.05  zmc  there  is  a  very  regular  decrease  of 
ductility,  the  latter  having  an  extension  of  0.00002,  or  only 
about  T^rJoorth  of  the  maximum.  From  61.05  to  88.88  zinc 
there  is  a  uniform  want  of  ductility,  the  figures  of  extension 
varying  from  0.00002  to  o.oooii.  From  88.88  zinc  to  pure 
zinc,  the  ductility  increases. 

245.  A  Summary  of  many  of  the  results  of  the  tests  which 
have  been  described  will  be  found  included  in  the  table  al- 
ready given  at  the  end  of  Chapter  V.,  in  which  the  brasses 
are  described. 


CHAPTER   XI. 

STRENGTH     OF    KALCHOIDS    AND     OTHER     COPPER-TIN-ZINC 

ALLOYS. 

246.  The  Kalchoids. — The  bronzes  and  brasses  were  not 
distinguished  by  early  Greek  and  Latin  writers,  who  applied 
the  same  names  to  both  (Greek,  Kalchos ;  Latin,  Acs.).  It 
has  also  been  common  to  add  to  the  copper-tin,  or  bronze, 
alloys  small  proportions  of  zinc,  and  lately,  to  the  copper-zinc 
alloys,  or  brasses,  small  quantities  of  tin,  thus  forming  an  in- 
termediate collection  of  indefinite  number  and  proportions,  to 
which  may  be  here  applied  the  indefinite  terms  of  the  ancients, 
and  which  may  be  called  the  kalchoids,  or  kalchoid  alloys. 
These  and  solders  and  other  copper-tin-zinc  alloys  naturally 
fall  into  one  group. 

The  effect  of  substituting  a  small  quantity  of  zinc  for  tin 
in  making  the  bronzes  is  not  perceivable  except  as  making 
them  a  little  less  subject  to  "  cold  shuts,"  or  blow-holes  and 
similar  defects,  making  them  a  little  softer  and  a  trifle  weaker 
and  giving  them  slightly  better  working  qualities  when 
turned  in  the  lathe  or  otherwise  shaped  with  cutting  tools. 
The  effect  of  substituting  a  small  proportion  of  tin  for  zinc  in 
the  brasses,  however,  is  very  marked,  causing  increased 
hardness,  strength,  rigidity  and  elasticity,  and,  if  the  propor- 
tions of  copper  and  zinc  are  about  equal,  making  the  alloy 
too  hard  and  brittle  to  work. 

In  general,  the  effects  of  the  two  metals,  zinc  and  tin, 
upon  copper  are  similar,  but  that  of  adding  tin  is  much  more 
observable  than  that  of  introducing  zinc.  It  was  found  in 
collating  the  results  of  investigations  made  by  the  Author  for 
the  U.  S.  Board  and  in  other  researches,  that  the  effect  of  one 
part  tin  is  nearly  equivalent  to  two  parts  of  zinc. 

These  facts  are  well  illustrated  in  the  account  of  that  work 


STRENGTH  OF  KALCHOIDS. 


415 


to  be  presented  in  the  present  chapter.     They  are  well  shown 
also,  in  experiments  on  "  sterro-metal." 

247.  Sterro-metal,  tested  at  Woolwich,  exhibited  a  te- 
nacity somewhat  variable  with  composition,  but  always  con- 
siderable, as  seen  below.*  Its  stiffness  and  resistance  to 
abrasion  were  also  found  to  be  very  great.  The  tenacity  may 
be  taken  at  an  average  of  60,000  pounds  per  square  inch 
(4,218  kilogs.  per  sq.  cm.),  its  elastic  limit  at  one-half  that 
amount,  and  its  elongation  at  0.07.  The  test  pieces  used 
were  three  diameters  long. 


TABLE  LXXVI. 

TENACITY   OF   STERRO-METAL. 


Breaking 
weight,  Ibs. 
per   square 
inch. 

Kilogs.  per 
square  cm. 

Ultimate 
elongation 
at  breaking 
point  in 
inches. 

Treatment 

Mixture. 

60,020 

4,213 

.1 

as  received. 

Austrian. 

46,060 

3,386 

.05 

j 

Copper,  60  ;  zinc,  39  ; 

\  cast  in  sand. 

iron,  3  ;  tin,  1.5. 

43,120 

3,032 

.015 

) 

I 

54,220 

52,080 

3,819 
3,662 

.016 

.02 

cast  in  iron. 
j  cast   in    iron   and 
(      annealed. 

1  Copper,  60;  zinc,  44; 
iron,  4  ;  tin,  2. 

62,720 

4,410 

•045 

forged  red  hot. 

\ 

70,806 

4078 

)  cast   in   iron   and 

"70  8d^ 

'  V  / 
e   T2I 

f      forged  red  hot. 

/^>°*f3 
76,160 

3,  *•* 

5,355 

Copper,  60  ;  zinc,  37  ; 
iron,  2  ;  tin,  I. 

84,920 

5,985 

Copper,  60  ;  zinc,  35  . 
iron,  3  ;  tin,  2. 

60,480 

76,160 
84,920 

4,252 

5,355 
5,9^5 

after    simple 
fusion, 
forged  red  hot. 
drawn  cold. 

]  Copper,  55.04  ;  spelter, 
y     42.36  ;    iron,   1.77  ; 
tin  .83. 

62,720 

4,410 

.... 

after    simple 

] 

fusion. 

73,680 

5,040 

forged  red  hot. 
drawn    cold     and 
reduced       from 

Copper,  57.63;  spelter, 
y     40.22;    iron,    1.86; 

82,880 

5,827 

....     \ 

100  to  77  trans- 

tin, 0.15. 

1 

verse     sectional 

area. 

} 

Strength  of  Materials  ;"  Anderson,  Lond.,  1872. 


41 6   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

This  greater  tenacity,  as  compared  with  brass  and  Muntz 
metal,  is  probably  partly  due  to  the  presence  of  iron,  but 
largely  also  to  the  one  or  two  per  cent.  tin.  As  will  be  seen 
later,  the  Author  has  obtained  higher  figures  by  the  use  of 
tin  alone. 

248.  The  Copper-Tin  Zinc  Alloys  were  made  the  sub- 
ject of  a  special  and  systematic  investigation,  at  the  request 
of  the  Committee  on  Alloys  of  the  U.  S.  Board  of  1875,  with 
a  view  to  the  determination,  not  simply  of  the  strength  and 
other  properties  of  specific  combinations,  but  to  ascertain  the 
law  governing  the  variation  of  such  useful  qualities  with  vari- 
ation of  composition,  in  such  manner  that,  by  the  study  of  a 
limited  number  of  these  alloys,  the  properties  of  all  possible 
combinations  of  the  three  metals  might  be  fully  determined. 
Before  entering  upon  this  investigation  it,  therefore,  became 
necessary  to  devise  a  plan  and  to  invent  a  method  of  research, 
which  should  enable  the  Author  so  to  choose  the  set  of  alloys 
to  be  studied  as  to  make  their  number  a  minimum,  while  so 
fixing  their  proportions  as  to  distribute  them  with  a  satisfac- 
tory degree    of   uniformity  over  the  whole  field  to  be  ex- 
plored, thus  making  the  research  complete  and  productive  of 
a   maximum    result    at   minimum    cost   of   time,   labor,  and 
money. 

249.  The  Plan  of  Investigation,  if  it  could  be  made  thus 
effective,  should  evidently  lead  not  only  to  the  determination 
of  the  strength  and  elasticity,   ductility  and  resilience,  and 
other  important  properties  of  all  possible  alloys  of  copper  with 
zinc,  copper  with  tin,  and  tin  with  zinc,  and  of  all  copper-tin- 
zinc  alloys,  but  should  also  reveal   the   composition   of  the 
alloy  of  maximum  strength  or  other  quality,  or  combination 
of  qualities,  that  could  possibly  be  formed  and  that  man  can 
make,  using  these  elements.     Such  a  plan  was  devised  by  the 
Author.     Its  principle  is  as  follows  :  * 

In  any  equilateral  triangle,  B,  C,  D,  Fig.  22,  let  fall  per- 
pendiculars from  the  vertices  to  the  opposite  sides,  as  for 

*  On  a  New  Method  of  Planning  Researches,  etc.,  by  R.  H.  Thurston.  Proc. 
Assoc.  for  Advancement  of  Science,  vol.  xxvi.  Trans.  Am.  Soc,  C.  E.  1881, 
No.  214. 


STRENG TH  OF  KALCHOIDS.  4 1  / 

example,  C  E.  From  any  point  within  the 
triangle,  A,  let  fall  perpendiculars  A  G, 
AH,A~F,  and  draw  A  B,  A  C,  AD  to 
the  vertices,  thus  obtaining  three  triangles, 
A  B  D,  ABC,  A  CD;  their  sum  is  equaled — i-i 
to  the  area  of  the  whole  figure  BCD.  FlG-  22- 

Now  we  have,  since  the  triangle  is  equilateral,  and 


CE  x  BD  _  A  F  x  BD       A  G   X  B  C      AH  x  CD 


CE  x  .££>  =  (AF+AG  +  AH)  x  BD\ 
and 


which  follows  wherever  the  point  A  may  be  situated  ;  it  is 
true  for  every  point  in  the  whole  area  BCD.  Assuming 
the  vertical  C  E  to  be  divided  into  100  parts  ;  then  A  F  + 


~AH  +  ~A~G  =  100  and          ,  ,        L,  measures  the  rela- 

100      100     100 

tion  of  each  of  the  altitudes  of  the  small  triangles  to  that  of 
the  large  one. 

But  we  may  now  conceive  the  large  triangle  to  represent 
a  triple  alloy  of  which  the  areas  of  the  small  triangles  shall 
each  measure  the  proportion  in  which  one  of  the  constituents 
enters  the  compound,  and 


B  CD  =  100  per  cent.  =  (A  F  +  A  G  +  A  H)  B D,  or 

CE  =  100  per  cent.  =  A^F  +  A~G  +  A  H  per  cent,  and 
the  altitude  of  each  small  triangle  measures  the  percentage 
of  some  one  of  the  three  elements  which  enter  that  alloy 
which  is  identified  by  the  point.  Thus  every  possible  alloy 
is  represented  by  some  one  point  in  the  triangle  B  CD,  and 
27 


41 8  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

every  point  represents  and  identifies  a  single  alloy,  and 
only  that.  The  vertices  B,  C,  £>,  in  the  case  to  be  here  con- 
sidered, represent  respectively,  copper  =  100,  tin  =  100, 
zinc  =  100. 

250.  Alloys  Chosen  for  Test. — Thus,  having  determined 
a  method  of  studying  all  possible  combinations,  the  Author 
next  prepared  to  examine  this  field  of  work  in  the  most 
efficient  and  complete  manner  possible,  with  a  view  to  deter- 
mining, by  the  study  of  a  limited  number  of  all  possible  cop- 
per-tin-zinc alloys,  the  properties  of  all  the  numberless,  the 
infinite,  combinations  that  might  be  made,  and  with  the  hope 
of  detecting  some  law  of  variation  of  their  valuable  qualities 
with  variation  of  composition,  and  thus  ascertaining  which 
were  the  most  valuable  for  practical  purposes. 

With  this  object  in  view,  the  triangle  laid  down  to  repre- 
sent this  research,  was  laid  off  in  concentric  triangles,  Fig.  23, 
varying  in  altitude  by  an  equal  amount — 10  per  cent. — on 
which  were  laid  out  the  following  series  of  alloys : 


FIG.  23. 


STRENGTH  OF  KALCHOIDS. 
TABLE    LXXVII. 

SCHEDULE   OF   COPPER- TIN-ZINC  ALLOYS  TESTED. 


419 


COPPER. 

ZINC. 

TIN. 

COPPER. 

ZINC. 

TIN. 

10 

10 

80 

30 

40 

30 

10 

2O 

70 

30 

50 

2O 

10 

30 

60 

30 

60 

10 

10 

40 

50 

40 

IO 

50 

10 

50 

40 

40 

20 

40 

10 

60 

30 

40 

30 

30 

10 

70 

20 

40 

40 

20 

10 

80 

10 

40 

50 

IO 

20 

IO 

70 

50 

IO 

40 

20 

20 

60 

50 

20 

30 

20 

30 

50 

50 

30 

20 

2O 

40 

40 

50 

40 

10 

20 

50 

30 

60 

10 

30 

2O 

60 

20 

60 

20 

20 

20 

70 

TO 

60 

30 

10 

30 

10 

60 

70 

10 

20 

30 

2O 

50 

70 

2O 

10 

30 

30 

40 

So 

10 

10 

These  alloys  were  first  tested  in  the  Autographic  Record- 
ing Machine,  and  their  strain-diagrams  carefully  studied.  It 
was  found  that  only  a  few  were  of  value,  and  that  the  alloys 
represented  by  that  part  of  the  field  lying  on  the  tin-zinc  side 
of  a  line  running  from  copper  =  70,  tin  =  30,  zinc  =  o,  to 
the  point  copper  =  40,  zinc  =  60,  tin  =  o,  were  too  soft  or 
too  brittle  and  weak  to  be  useful.  The  research  was  now  re- 
stricted to  the  examination  of  alloys  lying  nearer  the  point 
copper  =  100,  i.e.,  the  upper  vertex  of  the  triangle  as  seen  in 
the  figure,  and  all  such  alloys  were  tested  by  tension,  com- 
pression, and  torsion,  and  by  transverse  stress. 

251.  Details  of  the  Work. — In  the  study  of  these  copper- 
tin-zinc  alloys,  the  same  general  method  of  experiment  was 
adopted  as  in  the  investigations  of  the  brasses  and  the 
bronzes  already  described.* 

To  ascertain  what  results  would  be  obtained  by  casting 
together  brass  and  bronze  of  known  properties,  the  first  series 


*  The  observer  entrusted  with  this  work,  under  the  direction  of  the  Author, 
was  Mr.  M.  I.  Coster,  M.  E. 


420  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

of  ternary  alloys  was  prepared  in  proportions  based  upon  results 
obtained  in  the  earlier  researches  relating  to  copper-tin  and 
copper-zinc  alloys  as  the  strongest,  the  weakest,  the  most  and 
the  least  resilient  alloys  respectively ;  and  by  various  com- 
binations of  these,  twelve  alloys  were  obtained. 

This  constitutes  the  first  series.  No.  5  (Cu  88.135,  Sn 
1.865,  Zn  10)  was  made  up  of  the  most  resilient  bronze  and 
brass ;  its  resilience  was  less  than  that  of  either  of  its  com- 
ponents. No.  6  (Cu  45,  Sn  23.75,  Zn  31.25),  composed  of 
the  least  resilient  bronze  and  brass,  was  less  resilient  than  the 
brass,  but  more  so  than  the  bronze.  No.  7  (Cu  66.885,  Sn 
1.865,  Zn  31.2),  formed  of  the  most  resilient  bronze  and  the 
least  resilient  brass,  was  much  less  resilient  than  the  bronze, 
but  considerably  more  so  than  the  brass.  No.  8  (Cu  66.25, 
Sn  23.75,  Zn  10)  was  made  of  the  least  resilient  bronze  and. 
the  most  resilient  brass.  It  was  less  resilient  than  either  the 
bronze  or  the  brass.  The  greatest  resistance  to  torsion  of 
all  the  bars  of  the  series  was  exhibited  by  No.  7,  and  the 
mean  of  its  torsional  moments  exceeded  that  of  all  the  others. 
It  was  of  a  more  homogeneous  structure,  and  may  be  con- 
sidered the  best  alloy  of  the  series.  No.  5  was  the  most 
ductile  and  the  most  resilient.  No.  12  (Tobin's  alloy,  Cu 
58.22,  Sn  2.30,  Zn  39.48)  was  shown  by  all  the  tests  to  be 
the  strongest  alloy.  It  exceeded  good  wrought  iron  in 
strength,  and  was  sufficiently  resilient  to  resist  shocks.  Its 
modulus  of  elasticity,  as  calculated  from  the  transverse  test, 
is  11,500,000  (metric,  808,450).  From  the  results  obtained,  it 
is  evident  that  it  does  not  necessarily  follow  that  two  alloys 
which  are  separately  good  and  strong,  or  poor  and  weak, 
will,  when  cast  together,  give  an  alloy  which  is  similarly 
strong  or  weak. 

A  second  series  was  next  tested,  to  afford  a  general  survey 
of  the  field  containing  what  were  known  to  be  good  alloys 
and  to  locate  approximately  the  position  of  the  best  com- 
positions. 

In  this  set,  36  alloys  were  made  by  all  possible  combina- 
tions obtainable  by  a  difference  of  10  per  cent,  in  the  three 
metals.  As  a  rule,  the  bars  of  this  series  were  not  as  strong 


STRENGTH  OF  KALCHOIDS.  421 

as  those  of  the  first  series ;  this  may  have  been  due  to  the 
fact  that  the  other  bars  were  cast  under  greater  pressure. 
It  was  noted  that  if  the  amount  of  tin  does  not  exceed  40 
per  cent.,  the  alloys  are  strengthened  by  an  increase  of  copper 
up  to  20  per  cent.  If  further  addition  of  copper  is  made  the 
alloys  become  brittle,  and  when  the  copper  amounts  to  50 
per  cent.,  compositions  are  obtained  which  are  practically 
worthless.  If  more  copper  is  added  the  alloys  increase  in 
strength  until  a  maximum  is  attained  for  the  greatest  per- 
centage of  copper  in  their  series,  i.  e.,  80  per  cent.  When  the 
amount  of  tin  exceeds  40  per  cent,  the  alloy  becomes  weaker 
as  the  percentage  of  copper  is  increased.  Up  to  20  per  cent, 
of  copper,  an  increase  of  tin  causes  a  decrease  of  strength  and 
an  increased  ductility.  Between  20  per  cent,  and  40  per 
cent,  of  copper,  the  alloys  become  stronger  for  an  increase  of 
tin  up  to  20  per  cent.  They  then  become  weaker  as  the  tin 
is  further  increased.  When  the  amount  of  copper  exceeds  40 
per  cent,  an  increase  of  tin  again  appears  to  weaken  the  alloy  ; 
this  is  only  true  when  the  least  quantity  of  tin  amounts  to  10 
per  cent.,  as  in  this  series.  The  results  of  tests  of  this  series 
show  that  more  than  five-sixths  of  the  alloys  in  the  field  here 
explored  are  comparatively  worthless. 

A  third  series  of  24  alloys  was  next  made  for  the  purpose 
of  locating  the  best  alloys  still  more  precisely,  and  to  deter- 
mine the  properties  of  those  lying  within  the  now  greatly 
restricted  field  of  investigation,  which  had  now  been  con- 
tracted to  a  small  fraction  of  the  total  area. 

A  line  was  drawn  from  45  per  cent,  copp'er  on  the  zinc 
side  of  the  triangle  to  72.5  per  cent,  of  copper  on  the  tin  side. 
These  points  represent  the  percentages  at  which  the  marked 
change  of  color  and  of  strength  in  the  brass  and  bronze  alloys 
takes  place.  The  alloys  of  this  series  were  all  located  in  that 
portion  of  the  field  containing  all  the  more  useful  composi- 
tions and  were  made  to  vary  in  composition  by  5  per  cent. 
The  castings  of  this  and  succeeding  series  had  smoother  sur- 
faces than  those  preceding.  Some  volatilization  of  zinc  took 
place  during  the  pouring  of  the  molten  metal  in  the  first 
three  numbers  of  the  series.  A  great  difference  was  noted  in 


42 2    MA  TERIA  L  S  OF  ENGINEERING— NON-FERRO  US  ME  TALS. 

the  results  obtained  from  the  upper  and  lower  ends  of  the 
bars  ;  the  upper  end  giving  the  best  figures.  The  difference 
between  the  strain-diagrams  of  these  two  portions  of  the  bar 
was  such  that  the  former  in  one  case  had  an  ordinate  of  0.92 
inch  at  the  elastic  limit  and  a  maximum  ordinate  of  1.76 
inches,  while  the  other  end  had  for  its  ordinate  at  the  elastic 
limit  1.38  inches  and  fora  maximum  ordinate  1.56  inches. 
The  general  laws  exhibited  by  the  curves  representing 
the  properties  of  alloys  of  copper,  tin,  and  zinc,  were  ap- 
proximately determined  from  the  tests  of  this  series.  For 
a  certain  amount  of  copper  (when  this  exceeds  50  per 
cent.)  an  addition  of  tin  increases  the  brittleness,  while 
zinc  increases  the  ductility  of  the  alloy.  If  the  amount 
of  copper  is  increased  it  is  necessary  also  to  increase  the 
tin  in  a  certain  ratio  in  order  to  obtain  an  alloy  of  about 
the  same  percentage  of  ductility.  It  was  shown  by  the  tests 
of  this  series  that  if  the  composition  has  80  per  cent,  of 
copper,  10  per  cent,  of  tin  will  make  it  quite  ductile,  while 
15  percent,  of  tin  will  render  it  rather  brittle.  Hence  the 
amount  of  tin  necessary  to  make  a  strong  alloy,  when  there  is 
80  per  cent,  of  copper,  lies  somewhere  between  10  per  cent, 
and  15  per  cent.,  and  an  alloy  composed  of  Cu  80,  Sn  12.5, 
Zn  7.5  was  taken  as  very  nearly  representing  the  best  pro- 
portions. 

Next,  a  fourth  series  was  made.  This  series  consisted  of 
but  five  alloys,  which  were  chosen  without  regard  to  regularity, 
but  to  determine  doubtful  points  previous  to  the  preparation 
of  the  final  series.  No.  I  (Cu  55,  Sn  0.5,  Zn  44.5)  contained 
but  0.5  per  cent,  of  tin,  and  is  the  only  instance  in  the  entire 
investigation  where  so  small  an  amount  of  any  of  the  metals 
was  introduced  in  an  alloy.  This  was  done  in  order  to  ascer- 
tain the  effect  of  so  small  a  percentage  when  added  to  an 
alloy  of  known  properties.  This  alloy  was  brass  (Muntz 
metal,  nearly),  and  0.5  per  cent,  of  tin  was  substituted  for 
zinc,  thus  leaving  but  44.5  per  cent,  of  zinc.  The  smallest 
quantity  of  zinc  in  any  bar  of  the  series  was  2.5  per  cent,  in 
No.  5  (Cu  82.5,  Sn  1-5,  Zn  2.5).  The  difference  in  ductility 
between  the  two  ends  of  the  bare  was  more  marked  in  No.  2 


STRENGTH  OF  KALCHOIDS.  423 

(Cu  67.5,  Sn  5,  Zn  27.5)  than  in  any  other  alloys  thus  far 
tested.  The  upper  end,  No.  2  A,  was  turned  in  the  auto- 
graphic machine  through  an  angle  of  70.8°,  while  the  lower 
end,  B,  broke  after  it  was  turned  through  7.5°,  the  latter 
being  only  about  10  per  cent,  of  the  former.  This  difference 
was  exhibited,  in  a  more  or  less  marked  degree,  by  all  the 
bars  of  this  series. 

Comparing  the  data  thus  obtained  by  test  of  the  several 
sets  of  alloys  made  as  above,  it  became  evident  that  all  the 
most  useful  alloys  are  located  between  the  line  drawn  from 
88  per  cent,  of  copper  on  the  bronze  side  of  the  triangle  to 
65  per  cent,  of  copper  on  the  brass  side,  and  from  83  per 
cent,  of  copper  on  the  bronze  side  to  55  per  cent,  on  the 
brass  side.  Twelve  alloys  in  this  part  of  the  field  were  next 
made,  varying  by  2.5  per  cent.,  omitting  those  which  had 
already  been  tested  and  a  few  not  absolutely  necessary  to  the 
determination  of  the  law  of  variation  of  strength.  The  re- 
sults obtained  fully  confirmed  previous  conclusions.  It  was 
found  that,  in  nearly  all  cases,  the  upper  portion  of  the  bar 
was  considerably  more  ductile  than  the  lower  and  also  gener- 
ally stronger.  All  the  alloys  of  this  series  were  strong ;  the 
strongest,  No.  I  (Cu  60,  Sn  2.5,  Zn  37.5),  had  a  mean  maxi- 
mum torsional  moment  of  216  foot-pounds  (tenacity  about 
40,000  Ibs.  or  2,892  kilogs.),  and  the  weakest,  No.  7  (Cu  72.5, 
Sn  10,  Zn  17.5),  122  foot-pounds  (tenacity  about  24,000  Ibs., 
or  1,672  kilogs.).  All  the  alloys  located  between  the  lines 
forming  the  boundaries  of  the  set  of  compositions  in  this 
series  are  useful  and  strong.  Commencing  with  the  strong 
brasses  on  one  side  of  the  triangle,  greater  strength  is  ob- 
tained when  any  appreciable  amount  of  tin  is  added ;  as  the 
quantity  of  tin  is  increased,  the  alloys  continue  to  be  superior 
in  strength  to  either  the  brasses  or  the  bronzes ;  but  their 
strength  gradually  decreases  with  the  diminution  of  the 
amount  of  zinc,  if  the  alloy  contains  more  than  60  per  cent. 
of  copper,  until  we  obtain  strong  bronzes  on  the  other  side  of 
the  field.  An  addition  of  tin  for  the  same  amount  of  copper, 
if  this  addition  does  not  exceed  30  per  cent.,  increases  the 
ductility  of  the  alloy.  In  alloys  containing  40  per  cent,  of 


424  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

copper  a  substitution  of  a  moderate  quantity  of  tin  for  zinc 
does  not  seem  to  affect  the  ductility.  If  the  alloys  contain 
more  than  40  per  cent,  of  copper,  an  increase  of  tin  causes  a 
decrease  of  ductility.  The  most  ductile  alloy  was  No.  8  B, 
2d  series  (Cu  10,  Sn  80,  Zn  10),  which  had  an  angle  of  tor- 
sion in  the  autographic  machine  of  418.4°  ;  no  other  alloy 
tested  contained  such  a  large  quantity  of  tin.  From  the  per- 
centage of  extensions  of  the  alloys  having  a  torsional  moment 
of  more  than  150  foot-pounds,  and  strength  of  more  than 
30,000  pounds  per  square  inch  (2,109  kilogs.  per  sq.  cm.),  four 
curves  of  maximum  strength  with  a  percentage  of  extension 
have  been  constructed  (Fig.  27).  The  lowest  curve  thus 
plotted  has  an  extension  of  0.03  per  cent,  and  connects  the 
points  representing  the  strong  brittle  alloys.  It  starts  at  43 
per  cent,  of  copper  on  the  brass  side  and  cuts  the  bronze  side 
of  the  triangle  at  77  per  cent,  of  copper.  The  other  curves 
have  an  extension  of  3,  7.3,  and  17  per  cent,  respectively. 
They  all  appear  to  converge  to  a  point  on  the  right  of  the 
brass  side  and  agree  nearly  with  arcs  of  circles  of  about  7 
inches  radius  on  the  scale  of  the  figure.  By  means  of  these 
curves  of  extension,  alloys  of  different  degrees  of  ductility  can 
be  selected.  The  effect  of  tin  upon  alloys  of  copper  and  zinc 
within  limits  may  be  compared  to  that  of  carbon  on  wrought- 
iron.  Commencing  with  brass  of  about  55  per  cent,  of  copper, 
which  is  of  itself  ductile  and  strong,  we  obtain  by  the  addition 
of  a  small  percentage  of  tin  an  alloy  of  much  greater  strength, 
having  a  higher  modulus  of  elasticity,  but  not  quite  as  ductile. 
By  further  addition  of  tin,  up  to  about  2.5  per  cent.,  the  alloy 
becomes  gradually  less  ductile,  but  it  increases  in  strength. 
But  if  more  tin  is  added,  we  obtain  compositions  which  be- 
come more  brittle  as  the  tin  is  increased,  and  at  the  same 
time  decrease  in  strength.  A  slight  modification  of  propor- 
tions often  causes  very  great  changes  in  the  properties  of  the 
alloys,  as  in  No.  I,  4th  series,  where  0.5  per  cent,  of  tin, 
added  to  ordinary  brass  produced  an  alloy  stronger  than 
wrought  iron. 

The  facts  thus  brought  out  are  best  exhibited  by  the  pro- 
file map  and  the  model  which  are  to  be  presently  described. 


STRENGTH  OF  KALCHOIDS. 


425 


252.  The  Method  of  Exhibiting  and  Recording  Results, 
which,  as  devised  by  the  Author  for  this  case,  was  intended 
so  to  present  the  data  secured  in  the  manner  described  that 
it  could  be  seen,  at  a  glance,  what  law,  if  any,  controlled  the 

FIG.  24. — COPPER-TIN-ZINC  ALLOYS. 


variation  of  strength,  or  of  the  quality,  with  change  of  com- 
position, and  that  the  investigator  could  readily  determine 
where  to  seek  the  alloy  possessing  a  maximum  of  any  quality, 
desirable  or  otherwise,  should  it  happen,  as  would  in  all  prob- 
ability be  the  case,  that  that  alloy  had  not  been  included 
among  those  studied  during  the  investigation.  The  plan 


426  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

finally  adopted  was  novel  but  as  thoroughly  satisfactory  as 
was  that  of  laying  out  the  work.  It  was  the  following : 

The  figures  obtained  by  the  test  of  alloys  studied  were 
inserted  upon  a  triangular  plan,  each  in  its  place  as  deter- 
mined, in  the  manner  described  in  Art.  249,  for  that  compo- 
sition. 

When  the  figures  thus  obtained  had  been  entered  on  the 
triangular  map,  lines  of  equal  strength,  of  equal  ductility,  or 
of  equal  resistance  could  be  drawn,  as  in  topographical  work 
lines  of  equal  altitude  are  drawn,  and  the  map  became  thus  a 
useful  representation  of  the  valuable  qualities  of  all  possible 
alloys. 

Figure  24  represents  such  a  map  *  of  all  copper-tin-zinc 
alloys.  The  scale  of  altitudes  is  obtained  by  considering  the 
relation  of  tension  to  torsion  resistance  as  25,000  pounds  per 
square  inch  (1,758  kilogrammes  per  square  centimetre)  for 
each  100  foot-pounds  (13.82  kilogrammetres)  of  torsional  mo- 
ment for  the  standard  test-specimen,  which  specimen  was 
turned  to  a  standard  gauge,  and  made  ^  inch  (1.84  cm.)  di- 
ameter and  i  inch  (2.54  cm.)  long  in  the  cylindrical  part  ex- 
posed to  strain. 

These  facts  were  also  exhibited  by  another  method  de- 
vised by  the  Author ;  thus  : 

Upon  a  triangular  metal  base,  laid  off  as  above,  erect  a 
light  metallic  staff  by  drilling  a  hole  for  its  support  at  each 
point  laid  down  as  representative  of  an  alloy  tested  ;  make 
the  altitude  of  each  of  these  wires  proportional  to  the  strength 
of  that  alloy.  There  is  thus  produced  a  forest  of  wires,  the 
tops  of  which  are  at  elevations  above  the  base-plane  propor- 
tional to  the  strengths  of  the  alloys  studied.  Similar  con- 
structions may  be  made  to  represent  the  elasticity,  the  duc- 
tility, or  any  other  property  of  all  these  alloys.  Next  fill  in 
between  these  verticals  with  clay,  or  better,  with  plaster,  and 
carefully  mould  it  until  the  tops  of  all  the  wires  are  just  vis- 
ible, shining  points  in  the  now  smooth  surface  of  the  model. 

*  Reports  of  U.  S.  Board  testing  Iron,  Steel,  etc.  Washington,  1878-1881. 
The  Strongest  of  the  Bronzes  ;  R.  H.  Thurston.  Trans.  Am.  Soc.  C.  E.  1881, 
no.  ccxlv. 


STRENGTH  OF  KALCHOIDS. 


427 


The  surface  thus  formed  will  have  a  topography  characteris- 
tic of  the  alloys  examined,  and  its  undulations  will  represent 
the  characteristic  variations  of  quality  with  changing  propor 
tions  of  the  three  constituents.    This  was  made  for  the  Author, 

FIG.  25. — MODEL  OF  COPPER-TIN-ZINC  ALLOYS. 


Zn. 


and  was  cast  in  an  alloy  of  maximum  tenacity,  the  plaster 
cast  made  as  above  being  used  as  a  pattern. 

Figure  25  is  a  representation  of  this  model  made  from  a 
photograph. 

253.  General  Deductions.— The  remarkable  variations  of 
quality  here  so  strikingly  shown  attracted  attention,  and  a 
further  investigation  was  made. 

These  alloys  were  purposely  made  without  other  precau- 


428  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

tions  than  those  observed  by  every  founder,  and  without  using 
deoxidizing  fluxes. 

The  data  obtained  were  consequently  quite  variable,  and 
the  result  of  this  work  indicated  that  the  same  alloy,  especially 
where  the  proportion  of  copper  is  great,  may  give  very  differ- 
ent figures  accordingly  as  it  is  more  or  less  affected  by  the 
many  conditions  that  influence  the  value  of  all  brass-foundry 
products. 

Some  variations  in  the  model  are  probably  due  to  such 
accidental  circumstances.  But,  allowing  for  minor  vari- 
ations, it  is  evident  that  the  alloys  of  maximum  strength  are 
grouped,  as  shown  in  Figures  24  and  25,  about  a  point  not 
far  from  copper  —  55,  zinc  =  43,  tin  =  2.  This  point  is  en- 
circled in  the  map,  Figure  24,  by  the  line  marked  65,000  pounds 
per  square  inch  (4,570  kilogs.  per  sq.  cm.)  tenacity,  and  repre- 
sented on  the  model,  Figure  25,  by  the  peak  of  the  mountain 
seen  at  the  farthest  side — the  copper-zinc  side. 

This  is  the  strongest  of  all  bronzes,  and  an  alloy  of  this 
composition,  if  exactly  proportioned,  well  melted,  perfectly 
fluxed,  and  so  poured  as  to  produce  sound  and  pure  metallic 
alloy,  with  such  prompt  cooling  as  shall  prevent  liquation,  is 
:he  strongest  bronze  that  the  engineer  can  make  of  these 
netals. 

The  Author  finally  made  this  alloy,  and  of  it  constructed 
the  model  represented  in  the  last  figure.  It  is  a  close-grained 
alloy  of  rich  color,  fine  surface,  and  takes  a  good  polish.  It 
oxidizes  with  difficulty,  and  the  surface  then  takes  on  a  pleas- 
ant shade  of  statuary  bronze  green. 

The  exact  composition  of  this,  which  the  Author  has  called 
the  "  maximum  alloy,"  was  not  considered  as  fully  determined 
by  this  preliminary  investigation.  The  metals  used  in  making 
it  were  commercial  copper,  tin,  and  zinc,  and  the  methods  of 
mixing,  melting,  and  casting  were  purposely  those  usual  in 
the  ordinary  brass  foundry,  and  necessarily  subject  to  some 
uncertainty  of  result. 

The  precise  location  of  this  "  strongest  of  the  bronzes" 
was  intended  to  be  made  in  an  independent  and  later  research, 
in  which  chemically  pure  metals,  more  carefully  handled,  and 


STRENGTH  OF  KALCHOIDS.  429 

especially  well  fluxed  with  phosphorus  or  other  effective 
flux,  should  be  used.  This  research  was  carried  out  several 
years  later,  under  the  eye  of  the  Author,  and  an  account  of  it 
is  given  later. 

Testing  the  alloy  above  referred  to,  it  was  found  to  have 
considerable  hardness  and  but  moderate  ductility,  though 
tough  and  ductile  enough  for  most  purposes ;  it  would  forge 
if  handled  skilfully  and  carefully,  and  not  too  long  or  too 
highly  heated,  had  immense  strength,  and  seemed  unusually 
well  adapted  for  general  use  as  a  working  quality  of  bronze. 
In  composition  it  is  a  brass,  with  a  small  dose  of  tin. 

The  alloy  made  as  representing  the  best  for  purposes  de- 
manding toughness,  as  well  as  strength,  contains  less  tin  than 
the  above  composition  (Cu,  55  ;Sn,  0.5  ;Zn,  44.5). 

It  hacia  tenacity  of  68,900  pounds  per  square  inch  (4,841 
kilogs.  per  sq.  cm.)  of  original  section,  and  92,136  pounds 
(6,477  kilogs.)  on  fractured  area,  and  elongated  47  to  5 1  per  cent, 
with  a  reduction  to  from  0.69  to  0.73  of  its  original  diameter. 

No  exaltation  of  the  normal  elastic  limits  was  observable 
during  tests  made  for  the  purpose  of  measuring  it  if  noted. 
This  alloy  was  very  homogeneous,  two  tests  by  tension  giving 
exactly  the  same  figure,  68,900.  The  fractured  surface  was 
in  color  pinkish  yellow,  and  was  dotted  with  minute  crystals 
of  alloy  produced  by  cooling  too  slowly.  The  shavings  pro- 
duced by  the  turning  tool  were  curled  closely,  like  those  of 
good  iron,  and  were  tough  and  strong. 

254.  The  Strain-Diagrams  from  the  autographic  ma- 
chine (No.  1,001)  are  shown  in  fac  simile  in  the  accompanying 
engraving.  The  tenacity,  as  estimated  from  the  resistance 
to  torsion,  is  nearly  equal  to  that  determined  by  direct  ex- 
periment, and  four  samples  tested  give  strain-diagrams  that 
are  all  nearly  precisely  alike.  They  exhibit  an  ill-defined 
elastic  limit,  e,  at  about  f  their  ultimate  resistance,  and  about 
the  same  as  a  piece  of  excellent  gun-bronze  (Cu,  90;  Sn,  10 
per  cent.),  1,252  A,  the  strain-diagram  of  which  lies  beside 
them  in  dotted  line.  The  elastic  resilience,  which  is  meas- 
ured by  the  area  of  the  curve  up  to  e,  is  superior  to  that  of 
the  gun-bronze,  and  the  elastic  range  is  seen  to  be  greater,  on 


43O  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

inspection  of  the  "  elasticity  lines,"  e  e .  In  ductility  they 
excel  1,252  A,  somewhat,  as  is  seen  by  comparing  1,001  A 
with  1,252  A.  Their  toughness  is  shown  by  the  great  area 
and  the  altitude  of  the  curve ;  their  excellence  of  quality  is 
also  shown  by  its  smoothness  of  outline.  The  homogeneous- 
ness  of  structure  is  exhibited  by  the  similarity  of  the  diagrams 
and  by  the  smoothness  of  the  bend  at  c,  which  marks  the 
elastic  limit. 

At /is  a  depression  of  the  normal  line  of  elastic  limits 
produced  by  17  hours  intermission  of  distortion  under  the 
load  there  carried.  This  slight  depression  marks  this  alloy  as 
one  of  the  "tin  class." 

Diagram  1,252  B  is  given  by  a  fine  gun-bronze;  1,001  x  is 
an  hypothetical  diagram,  such  as  would  be  produced  were  the 
alloy  here  described  so  carefully  fluxed  and  cast  as  Jo  exceed 
in  strength  the  unfluxed  alloys  actually  tested,  1,001  A,B,  C, 
D,  in  as  great  a  proportion  as  1,252  B  excels  1,252  A.  The  dia- 
gram 1,001  y  would  be  produced  were  it  possible  to  so  far 
improve  this  alloy  as  to  cause  it  to  excel  1,252  A  as  greatly 
as  No.  1,001  actually  did  excel  the  gun-bronze  made  under 
similar  conditions  in  this  preliminary  rough  work.  No.  1,004 
A  is  copied  to  exhibit  the  superiority  of  the  alloy  1,001  to 
one  but  little  removed  from  it,  and  which  is  considered  by 
some  brass  founders  an  excellent  composition. 

255.  The  Tenacities  of  the  Strong  Alloys  of  copper,  tin, 
and  zinc,  as  obtained  by  the  investigation  just  described,  are, 
as  has  been  seen,  quite  variable,  and  the  result  of  the  whole 
has  been  fully  confirmatory  of  Major  Wade's  conclusion  rela- 
tive to  useful  alloys  of  copper  with  softer  metals :  that  they 
are  subject  to  great  variation  of  quality,  as  ordinarily  made, 
and  that  it  is  impossible  to  predict  with  certainty  the  sound- 
ness, the  uniformity,  and  homogeneousness,  or  the  strength 
of  any  casting  in  bronze  or  brass.  A  study  of  the  figures  here 
obtained,  however,  and  of  the  map  or  model  exhibiting  them, 
shows  that,  with  good  castings  of  any  of  the  more  valuable 
compositions,  certain  methods  of  variation  and  a  general  law 
may  be  formulated.  Thus,  for  true  bronzes  containing  usual 
amounts  of  tin,  the  tenacity,  as  such  castings  are  commonly 


STRENGTH  OF  KALCHOIDS. 


431 


432  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS 

made  in  the  course  of  every-day  business  in  the  foundry,  should 
be  about — 

Te  =  30,000  +  1,000  /; 


where  t  is  the  percentage  of  tin,  and  not  above  15  per  cent. 
Thus  gun-bronze  can  be  given  about  30,000  -f  (1,000  x  10) 
=  40,000  pounds  per  square  inch,  if  well  made.  In  metric 
measures 

T*  =  2,109  +  70.3  A 

giving  for  good  gun-metal  2,109  x  7°3  =  2>8i2  kilogs.  per 
sq.  cm. 

For  brass  (copper  and  zinc)  the  tenacity  may  be  taken  as 

Tx  =  30,000  +  500  z ; 

where  the  zinc  is  not  above  50  per  cent.;  and 
Tzl  =  2,109  +  35-15  *• 

Thus  copper  70,  zinc  30,  should  have  a  strength  of  30,000 
+  (500  x  30)  =  45,000  pounds  per  square  inch,  or  2,109  -f 
(35- 1 5  x  3°)  =  3^65  kilogrammes  per  square  centimetre. 

Referring  once  more  to  Figures  24  and  25,  it  is  seen  that  a 
line  of  maximum  elevation  crosses  the  field  marking  the  crest 
of  the  mountain  in  Figure  25,  of  which  the  "  maximum  bronze  " 
is  the  peak.  This  line  of  valuable  alloys  may  be  practically 
covered  by  the  formula : 

M  —  z  -f  3  /  =  Constant  =  55, 

in  which  z  is  the  percentage  of  zinc,  and  t  that  of  tin.  Thus 
a  maximum  is  found  at  about  /  =  o,  z  =  55,  while  the  other 
end  of  the  line  is  z  =  o,  t  =  18. 


STRENGTH  OF  KALCHOIDS.  433 

Along  this  line  the  strength  of  any  alloy  should  be  at  least 
Tm  =  40,000  +  500  *. 
Tm*=  2,812  f  35-15  ^ 

Thus  the  alloy  z  —  i,  t  =  18  will  also  contain  copper  = 
100  —  19  —  81,  and  this  alloy  Cu,  81  ;  Zn,  I  ;  Sn,  18,  should 
have  a  tenacity  of  at  least 

Tm  —  40,000  +  (500  x  i)  =  40,500  Ibs.  per  sq.  in. 
T*m  =  2,812  +  (35.15  x  i)  =  2,847  kilogs.  per  sq.  cm. 

The  alloy  Cu,  60;  Zn,  5  ;  Sn,  16,  should  have  at  least  the 
strength 

Tm  =  40,000  +  (500  x  5)  =  42,500  Ibs.  per  sq.  in. 
Tlm  =  2,812  +  (35.15  x  5)  =  2,988  kilogs.  per  sq.  cm. 

while  the  alloy  Zn,  50  ;  Sn,  2  ;  Cu,  48,  should  give,  as  a  mini- 
mum per  specification  : 

Tm  —  40,000  +  (500  x  50)  =  65,000  Ibs.  per  sq.  in. 
Tlm  =  2,812  +  (35.15  x  50)  =  4,570  kilogs.  per  sq.  cm. 

These  are  rough  working  formulas  that,  while  often  de- 
parted from  in  fact,  and  while  purely  empirical,  may  prove  of 
some  value  in  framing  specifications.  The  formula  for  the 
value  of  Tm  fails  with  alloys  containing  less  than  I  per  cent,  tin, 
as  the  strength  then  rapidly  falls  to  t  —  o. 

The  table  which  follows  will  present,  in  convenient  form, 
probably  fair  minimum  values  to  be  expected  when  good 
foundry  work  can  be  relied  upon,  and  may  ordinarily  be  used 
in  specifications  with  the  expectation  that  a  good  brass-founder 
will  be  able  to  guarantee  them. 
28 


434  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE    LXXVIII. 

MINIMUM   TENACITY    OF   ALLOYS. 


ALLOY. 

TENACITY.  —  Probable  Minimum. 

Cu. 

Zn. 

Sn. 

Lbs.  per  sq.  in. 

Kgs.  per  sq.  cm. 

IOO 

6 

o 

30,000 

2,109 

95 

5 

0 

32,500 

2,285 

90 

10 

o 

35,ooo 

2,460 

85 

15 

o 

37,500 

2,636 

9° 

0 

IO 

40,000 

2,812 

95 

o 

5 

35,000 

2,460 

97i 

o 

2* 

32,500 

2,285 

90 

5 

5 

37,500 

2,636 

85 

IO 

5 

40,000 

2,8l2 

75 

20 

5 

45,000 

3,163 

68 

30 

2 

47,000 

3,304 

64 

35 

I 

48,500 

3,410 

-60 

40 

0 

50,000 

3,515 

256.  Ductility. — The  ductility  of  these  alloys  is  a  subject 
of  as  much  interest  to  the  engineer  as  their  strength  ;  and  in 
this  quality  the  ternary  alloys  are  as  variable  as  in  every  other. 
Referring  again  to  the  map,  Figure  26,  it  is  seen  that  a 
closely  grouped  set  of  slightly  curved  and  slowly  converging 
lines  cross  it  from  tin  =  25,  to  zinc  —  55,  the  mean  line  having 
an  equation  nearly  2.2/  +  z  —  55.  Along  this  line  the  alloys 
have  immense  tenacity,  as  exhibited  by  the  fact  that  some  of 
them,  if  not  nearly  all,  are  too  hard  to  be  cut  by  steel  tools, 
and  in  shaping  them  only  grinding  tools — either  the  emery 
wheel  or  the  grindstone — could  be  used,  and  even  then  with 
most  unsatisfactory  results.  Yet  such  was  the  brittleness  of 
these  metals  that  no  reliable  test  of  their  strength  could  be 
obtained.  The  strain-diagrams  obtained  were  straight,  and 
nearly  vertical  lines,  terminating  suddenly,  when  the  piece 
snapped,  without  indication  of  approach  to  an  elastic  limit. 
They  were  perfectly  elastic  up  to  the  point  of  fracture,  but 
were  so  destitute  of  resilience  that  no  use  can  probably  be 
made  of  them  by  the  engineer.  Their  brittleness  was  such 
that  they  would  often  break  in  the  mould  by  contraction  in 


STRENGTH  OF  KALCHOIDS. 


435 


cooling,  although  cast  in  a  straight  bar.  In  some  cases  they 
crack  by  the  heat  of  the  hand,  and  were  broken  at  one  end 
by  the  jar  transmitted  from  a  light  blow  struck  at  the  other 
end.*  The  border  line  of  this  valueless  territory  is  shown 

FIG.  27. — DUCTILITY  OF  COPPER-TIN-ZINC  ALLOYS. 


on  the  map  by  a  slightly  curved  dotted  line  to  which  a  line 
having  the  equation  2.5/  -f  s  =  55  is  nearly  tangent.  The 
alloys  lying  along  this  line  have  nearly  equal  ductility,  ex. 
tending,  according  to  measurements  obtained  by  the  auto, 
graphic  machine,  about  .03  of  one  per  cent. 

*  Report  to  U.  S.  Board.     Figure  from  the  R.R.  Gazette. 


436  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Above  this  line  is  another  having  nearly  the  equation 
4^  +  2  =  50,  which  last  line  is  that  of  equal  ductility  for  alloys 
exhibiting  extensions  of  3  per  cent.  Still  nearer  the  "pure 
copper  corner"  is  a  line  fairly  representing  alloys  containing 
about  33^  +  z  —  48,  and  along  which  the  extensions  were  7.3 
per  cent.,  and  another  such  line  extending  from  standard  gun- 
metal  compositions  on  the  one  side  to  Muntz  metal  on  the 
other — Cu  90,  Sn  10,  to  Cu  55,  Zn  45, — of  which  the  equa- 
tion is  nearly  4.5^  +  s  =  45,  represents  alloys  averaging  an 
extension  of  17  per  cent.  These  lines  are  best  seen  on  the 
sheet  of  extensions,  Fig.  28.  All  alloys  lying  above  the  line 
taken  here  as  a  boundary  line  give  figures  for  tenacity  that  ex- 
ceed 30,000  pounds  per  square  inch  (2,109  kilogs.  per  sq.  cm.). 

The  addition  of  tin  and  of  zinc  to  cast  copper  thus  in- 
creases tenacity  at  least  up  to  a  limit  marked  by  the  line 
3^  +  2=  55  ;  but  the  influence  of  tin  is  nearly  twice  as  great 
as  that  of  zinc,  and  the  limit  of  useful  effect  is  not  reached  in 
the  latter  case  until  the  amount  added  becomes  very  much 
greater  than  with  the  former  class— the  copper-tin  alloys. 
Brasses  can  be  obtained  which  are  stronger  than  any  bronzes, 
and  the  ductility  of  the  working  compositions  of  the  former 
class  generally  greatly  exceeds  that  of  the  latter.  Ternary 
alloys  may  be  made  containing  about  4?  +  z  =  50,  which  ex- 
ceed in  strength  any  of  the  binary  alloys,  and  compositions 
approaching  copper,  55;  tin,  2;  zinc,  43;  may  be  made,  of 
extraordinary  value  for  purposes  demanding  great  strength, 
combined  with  the  peculiar  advantages  offered  by  brass  or 
bronze.  The  addition  of  one-half  per  cent,  tin  to  Muntz 
metal  confers  vastly  increased  strength. 

The  range  of  useful  introduction  of  tin  is  thus  very  much 
more  restricted  than  that  of  zinc;  alloys  containing  12  to  15 
per  cent,  tin  are  so  hard  and  brittle  as  to  but  rarely  find  ap- 
plication in  the  arts,  while  brass  containing  40  per  cent,  zinc, 
is  the  toughest  and  most  generally  useful  of  all  the  copper 
zinc  "  mixtures."  The  moduli  of  elasticity  of  these  alloys  are 
remarkably  uniform,  more  than  one-half  of  all  those  here 
described  ranging  closely  up  to  fourteen  millions,  or  one-half 
that  of  well-made  steel-wire.  The  moduli  gradually  and 


STRENGTH  OF  KALCHOIDS.  437 

slowly  increase  from  the  beginning  of  the  test  to  the  elastic 
limit. 

The  Fracture  of  these  Alloys  is  always  illustrative  of  their 
special  characteristics.  Those  broken  by  torsion  in  the 
autographic  testing  machine  were,  if  brittle,  all  more  or 
less  conoidal  at  the  break ;  ductile  alloys  yield  by  shearing  in 
a  plane  at  right  angles  to  the  axis  of  the  test  piece ;  the  for- 
mer resemble  cast  iron  and  the  latter  have  the  fracture  of 
wrought  iron.  Every  shade  of  gradation  in  this  respect  is 
exhibited  by  an  observable  modification  of  the  surface  of 
fracture  varying  from  that  characteristic  of  extreme  rigidity 
and  brittleness,  through  an  interesting  variety  of  intermediate 
and  compound  forms  to  that  seen  in  fracture  of  the  most 
ductile  metals. 

257.  Possibilities  of  Improvement. — The  tenacities  and 
ductilities  given  are  within  the  best  attainable  figures  where 
they  relate  to  the  most  valuable  working  bronzes  and  brasses. 
These  figures  represent  the  result  of  ordinary  founders'  work ; 
and  metals  rich  in  copper,  made  with  no  greater  precaution 
against  oxidation  and  liquation  than  is  usual  in  brass  foun- 
dries, may  be  vastly  improved  by  special  treatment  sug- 
gested, by  using  pure  ingot  metals,  fluxing  carefully,  as 
with  phosphorus  or  manganese,  casting  in  chills,  rapid  cool- 
ing, and  finally  rolling,  or  otherwise  compressing,  either  hot  or 
cold. 

Unannealed  copper  wire  is  ^reported  by  Baudrimont*  as 
having  a  tenacity  of  about  45,000  pounds  per  square  inch 
(3,163  kilogs.  per  sq.  cm.),  and  Kirkaldy  reports  28.2  tons  per 
square  inch  (63,168  pounds  per  square  inch,  4,440  kilogs. 
per  square  cm.),  the  wires  having  diameters  of  0.0177  and 
0.064  inches  (0.044  and  0.165  cm.)  respectively. 

A  way  should  be  found  to  secure  equal  purity,  homo- 
geneousness,  and  density  in  cast  copper,  and  such  metal 
should  then  possess  tenacity  and  toughness  equal  to  that  of 
rolled  metal.  Gun-bronze,  which  ordinarily  has  a  tenacity  of 
about  35,000  pounds  per  square  inch  (2,460  kilogs.  per  sq, 
cm.)  has  been  made  at  the  Washington  Navy  Yard,  by  skil- 


*  Annales  de  Chiinie,  1850. 


OF  THE        ^       >v 

{UNIVERSITY) 


438    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

ful  mixture,  melting  and  pouring,  and  by  the  Author,  also,  to 
attain  a  tenacity  of  above  60,000  pounds  (4,218  kilogs.). 

The    effect    of    thorough    fluxing   with  deoxidizing   sub- 
stances is  so  important  that  no  founder  can  safely  neglect  it. 

FIG  28. 
DUCTILITY  OF  COPPER-TIN-ZINC  ALLOYS. 


COPPER 


Bronzes  fluxed  with  phosphorus,  arsenic,  and  manganese, 
have  been  given  fifty  per  cent,  higher  tenacity  than  the  or- 
dinary unfluxed  alloy,  and  the  addition  of  a  little  iron,  as  in 
the  so-called  "  sterro-metal  "  of  the  Baron  de  Rosthorn,  and 
in  Parson's  "  Manganese  Bronze,"  has  still  further  strengthened 
the  copper-tin-zinc  alloys. 

Dr.  Anderson    made  experiments  at  Woolwich,  showing 


STRENGTH  OF  KALCHOIDS.  439 

an  increase  of  strength  of  sterro-metal,  by  forging,  to  the 
extent  of  25  per  cent.,  and  by  drawing  cold  of  40  per  cent. 
Brass,  containing  copper,  62  to  70,  zinc,  38  to  30,  attains  a 
strength  in  the  wire  mill  of  90,000  pounds  per  square  inch,  and 
sometimes  of  100,000  (6,327  to  7,030  kilogs.  per  sq.  cm.),  and 
these  alloys  should  be  made  equally  tenacious  in  the  casting. 
The  Author  has  no  doubt  that  the  methods  indicated  as  those 
best  adapted  to  secure  dense,  strong  and  tough  metal  will 
yet  be  found  capable  of  yielding  alloys  of  more  than  double 
the  strength  representative  of  what  is  now  ordinary  brass- 
founders'  work.  It  should  be  possible  to  secure  copper-tin- 
zinc  alloys  having  tenacities  represented  by : 

'  Tmm  =  60,000  +  I  ,ooo/  +  500  z, 
TImm  =4,218  +-  70.3^  +  35-15^ 

throughout  that  area  on  the  map  representing  the  most  use- 
ful alloys,  from  copper,  100,  to  4/  +  z  =  50. 

Manufacturers  of  special  bronzes  are  approaching  this  de- 
gree of  excellence. 

In  the  working  of  copper  in  the  foundry  the  melter  meets 
with  difficulty  from  the  formation  of  either  the  oxide  or  car- 
bide. Could  he  secure  immunity  from  combination  with  one 
or  the  other  of  these  elements,  he  would  find  innumerable 
uses  for  cast  copper. 

The  general  character  and  the  method  of  variation  of 
strength  and  ductility  of  the  alloys  of  copper,  tin,  and  zinc 
are  so  well  exhibited  by  the  illustrations  presented,  that  no 
difficulty  will  be  met  with  by  the  engineer  in  the  endeavor  to 
select  the  alloy  best  adapted  to  any  specific  purpose  where 
such  an  adaptation  is  determined  by  physical  qualities  alone. 
Caution  must  be  used  in  selecting  alloys  where  great  strength 
is  demanded,  since  a  slight  change  of  composition  by  the  ad- 
dition of  tin  or  zinc  may  make  a  serious  change  in  the  direc- 
tion of  lessened  ductility  and  toughness.  The  engineer  will 
rarely  use  those  lying  on  the  tin  and  zinc  side  of  the  line  of 
alloys  having  0.07  (7  per  cent.)  ductility,  as  on  Figs.  27  and  28. 
Extraordinary  care  must  be  taken  in  making  the  strongest  alloys. 


44°  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Alloys  to  be  hammered  or  rolled  will  be  found  more  diffi- 
cult to  work  as  the  percentage  of  tin  is  increased,  and  the 
minutest  addition  of  tin  to  the  brasses  usually  rolled  is  found 
to  sensibly  decrease  their  manageability. 

258.  The  "Maximum  Bronzes"  form  a  group  demand- 
ing special  consideration  as  including  a  collection  of  generally 
unfamiliar  but  exceptionally  valuable  alloys. 

The  work  planned  by  the  Author  in  the  investigation  of  this 
part  of  the  subject  was  left  incomplete  by  the  U.  S.  Board,  but 
was  continued,  as  opportunity  offered,  at  intervals  up  to  the 
year  1884.*  The  position  and  characteristics  of  the  strongest 
possible  alloys  of  the  three  metals  constituting  the  "Kalchoids" 
having  been  determined  with  a  fair  degree  of  accuracy,  as  al- 
ready described,  the  next  step  was  to  ascertain  what  modifi- 
cations might  be  produced  in  them  by  careful  fluxing  and  the 
use  of  still  more  carefully  prepared  alloys.  This  later  study 
was  made  in  the  years  1882-3,  in  the  same  manner  as  the 
earlier  investigations  for  the  U.  S.  Government,  at  the  sug- 
gestion and  under  the  supervision  of  the  Author,  by  Mr.  W. 
E.  H.  Jobbins,  whose  report  is  here  abridged. f 

The  area  chosen  as  the  field  of  this  investigation  was  a 
small  triangular  portion  surrounding  the  peak  of  the  moun- 
tain, Fig.  25,  marked  65,000  on  Fig.  24,  as  this  area  embraces 
all  that  portion  of  the  field  in  which  the  most  valuable  alloys 
had  been  proven  to  be  located.  The  data  obtained  gave  ex- 
ceedingly high  figures,  the  lowest  average  value  of  tenacity 
being  above  50,000  pounds  per  square  inch  (3,515  kilogs.  per 
sq.  cm.)-  As  this  research  extended  over  a  very  limited  area, 
it  was  possible  to  conduct  the  investigation  with  much  greater 
exactness  than  before,  and  thus  settle  the  composition  of  the 
"  strongest  of  the  bronzes." 

The  metals  varied  with  differences  of  but  one  per  cent.; 
23  combinations  were  chosen  ;  2  test-pieces  were  made  of  each 

*  The  U.  S.  Board  was  strangled  by  refusal  of  appropriations,  leaving  the 
work  in  hand  unfinished.  Some  of  the  work  necessary  to  the  presentation  of  the 
reports  actually  made  was,  however,  concluded  by  the  Author,  at  some  expense, 
in  the  Mechanical  Laboratory  of  the  Stevens  Institute  of  Technology. 

f  "  Investigation  Locating  the  Strongest  of  the  Bronzes,"  J.  F.  I.,  1884. 


STRENGTH  OF  KALCHOIDS. 


441 


composition,  making  46  test-pieces.  Usually,  the  data  obtained 
from  two  specimens  of  the  same  composition  agreed  so  closely 
that  the  average  value  was  safely  taken  ;  but,  when  there  was 
a  marked  difference,  the  data  agreeing  more  closely  with  the 
results  anticipated  from  analogy  were  adopted,  and  the  other 
value  rejected  as  being  probably  erroneous.  The  copper  em- 
ployed was  from  Lake  Superior,  the  zinc  from  Bergen  Port. 

In  the  use  of  tin,  phosphorus  was  added  to  give  soundness 
in  these  copper-tin  and  copper-tin-zinc  alloys,  which  are  so 
liable  to  be  made  seriously  defective  by  the  absorption  of  oxy- 
gen and  the  formation  of  oxide.  It  has  been  found  possible  to 
produce,  on  a  commercial  scale,  an  alloy  of  phosphorus  and 
tin,  which,  while  containing  a  maximum  percentage,  does  not 
lose  phosphorus  when  remelted.  The  best  proportions  for 
practical  purposes  are  said  to  be  tin  95  per  cent,  and  phos- 
phorus 5  per  cent. 

After  careful  study,  the  following  limits  of  the  field  were 
decided  upon:  Copper,  maximum  60,  minimum  50;  Zn,  48 
and  38  ;  Sn,  5  and  o.  These  limits  include  the  best  alloys  for 
purposes  demanding  toughness  as  well  as  strength. 

The  compositions  are  given  in  the  following  table : 

TABLE   LXXIX. 

BEST  COPPER-TIN-ZINC  ALLOYS,    OR   KALCHOIDS. 


NO. 

cu. 

ZN. 

SN. 

NO. 

cu. 

-N. 

SN. 

NO. 

CU. 

ZN. 

SN. 

I 

55 

43 

2 

9 

53 

43 

4 

17 

58 

40 

2 

2 

54 

44 

2 

IO 

55 

4i 

4 

18 

54 

45 

I 

3 

54 

43 

3 

II 

57 

4i 

2 

19 

53 

44 

3 

4 

55 

42 

3 

12 

57 

43 

0 

20 

54 

42 

4 

5 

56 

42 

2 

13 

55 

45 

O 

21 

5<> 

41 

3 

6 

56 

43 

I 

14 

52 

46 

2 

22 

57 

42 

i 

7 

55 

44 

I 

15 

52 

43 

5 

23 

5« 

41 

I 

8 

53 

45 

2 

16 

55 

40 

5 

The  castings  were  made  much  as  in  all  the  earlier  investi- 
gations, the  same  precaution  being  taken  to  prevent  volatili- 
zation of  zinc,  and  care  was  taken  to  secure  rapid  cooling  to 
prevent  liquation.  All  the  compositions  thus  made  were 


442  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


strong  and  usually  tough  ;  all  could  be  turned  and  worked 
safely,  and  all  were  evidently  of  commercial  value  for  the  pur- 
poses of  the  engineer.  All  test-pieces  were  sound,  and  even 
microscopic  examination  revealed  no  defects  in  structure. 
The  investigation  was  made  by  the  use  of  the  Author's  auto- 
graphic machine  as  permitting  most  rapid  work  and  most  ex- 
act determinations  of  quality  and  behavior,  especially  as  to 
the  latter  near  the  elastic  limit.  The  samples  were  all  re- 
duced to  the  standard  form  and  size. 

259.  Results  of  Tests. — The  formula  used  is  M  —  wJi  + 
/;  where  w  =  moment  necessary  to  deflect  the  pencil  one 
inch  ;  h  =  height  of  the  curve  above  the  base  line  al.  0r,  f  = 
friction  in  foot-pounds,  and  M  is  the  total  torsional  moment. 

In  this  case,  w  —  96.93  foot-pounds,  and/"=  4.75,  h  being 
measured  on  the  strain-diagram  of  each  test-piece.  To  obtain 
the  required  values  of  T the  formula  T  —  [300— J^#J  M*  in 
which  M  is  known,  and  dr  is  measured  directly  from  the 
autographic  record ;  T  is  the  calculated  tenacity.  The 
values  of  M,  T,  Be  and  0r,  the  total  moment,  the  approximate 
tenacity,  and  the  angles  of  torsion  at  the  elastic  limit  and  at 
rupture,  have  been  included  in  the  following  table : 

TABLE  LXXX. 

STRENGTH    OF    BEST    COPPER-TIN-ZINC  ALLOYS  OR  KALCHOIDS. 


| 

ORIGINAL 

STRESS   IN   TORSION. 
FOOT-POUNDS. 

M. 

APPROXIMATE 
STRESS    IN    TENSION. 
FOOT-POUNDS. 

ANGLES. 

MARK. 

" 

Ultimate. 

Average. 

Ultimate. 

Average. 

Oe 

0,- 

IXI           A 

270.208 
251.922 

261.065 

77,309 
72,301 

74,805 

•5° 

43° 
40 

OB             A 

178.321 
208  .  400 

193.369 

53,946 

59,810 

56,653 

.  i 
0.7 

5-05 
40 

Z3              A 

251.922 
219  935 

235-929 

75,576 
65,980 

70,778 

13-77 

10 

J4               * 

243.392 
258.319 

250.  851 

73,oi7 
74,9*2 

73,965 

2 
2 

19.8 
30-3 

*  This  relation  between  torsional  and  tensional  resistances  was  obtained  by 
experiment  on  the  machine  used  in  this  investigation.  Trans.  Am.  Soc.  C.  E., 
no.  clxiii.,  vol.  vii.,  1878. 


STRENGTH  OF  KALCHOIDS. 
TABLE    LXXX.— Continued. 


443 


ORIGINAL 
MARK. 

STRESS  IN  TORSION. 
FOOT-POUNDS. 
M. 

APPROXIMATE 
STRESS  IN  TENSION. 
FOOT-POUNDS. 
T. 

ANGLES. 

Ultimate. 

Average. 

Ultimate. 

Average. 

oe 

Qr 

*'          £ 

268.881 
263.543 

266.212 

75,824 
75,109 

75,467 

4.6° 

2 

55° 
46 

06              A 

227.689 
220.612 

224.151 

64,208 
63,193 

63,700 

2.05             53.3 
2               i      42.1 

K7    '         A 

286.847 
250-855 

268.851 

80,910 
70,  741 

75,826 

2 
2 

54 
53 

RS              A 

194.634 
I84-3JI 

189.488 

58,390 
55,299 

56,844 

2 
2.69 

9.1 

5  72 

••               5 

222.853 
230.597 

226.725 

66,853 
69,179 

68,017 

1-5 
1.79 

5-78 
4-5 

Lio            * 

249.014 

252.881 

250.948 

74,704 
75,864 

75,284 

2.1 

2.8 

4.6 

8.8 

Zl!                * 

260  .  645 
237.382 

249.014 

74,269 
63,964 

69,116 

2.4 
1.9 

39-8 

35 

DB             * 

227.689 
241.259 

234-474 

61,020 
61,762 

61,390 

2-3 

1.6 

95-2 
I3I-4 

M  13           * 

227.689 

20S  .  303 

217.996 

64,208 
57,908 

61,058 

2 
I.I 

52-4 
65 

UI4            £ 

163.715 

177.185 

170.^50 

49,  "3 

53,155 

51,139 

2-3 
2 

4-9 

7-2 

V.S            £ 

189.886 
227.689 

208.788 

56,965 
68.306 

62,636 

2.6 
2 

4 

5 

Ni6           * 

225.750 
253.198 

239-974 

67,725 
75,959 

71,842              '* 

3.8 
6.8 

A  17            A 

227.689 
250.952 

238.771 

68,344             '\ 
73,4"°                                   -° 

54 
43-2 

Pi8            A 

254.829 
260.645 

259-737 

72,871 
.71,501 

72,186          ;J 

43  4 
54 

T,9            A 

231.566 
196.671 

214.  119 

69,459 
59,001 

64,230 

.4 

8 
4.8 

QBO        A 

229.628 
258.707 

244.168 

68,888 
77,612 

73,250 

.6 

.8 

6.4 

7-2 

HBI         A 

283  .  908 
229    628 

266.768 

81,381 
68,888 

75,13? 

2-9 

2.4 

1 

EBB         A 

305-233 
221.773 

263  .  508 

85,770 
60,986 

73,378 

2                       56 

2.5            76 

B33            £ 

225.750 
175.247 

200.499 

63,084 
45,038 

54,061 

i  6       ,     63 

1.2            !     128 

The  neck  subjected  to  distortion  is  in  all  cases,  one  inch 
(2.54  cm.)  long  between  shoulders  and  ^  inch  (1.5875  cm.)  in 
diameter. 

260.  Discussion. — It    proved,    notwithstanding   the   pre- 


444  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 

cautions  taken  in  making  these  alloys,  to  be  a  matter  of  some 
difficulty  to  decide  satisfactorily  the  relative  positions  of  the 
alloys  studied.  Nos.  7  and  22  were  the  best  alloys  made. 

No.  7  was  a  fine  grained  alloy,  with  a  smooth,  even  fract- 
ure, tough  fibrous  appearance,  and  twisted  apart  slowly  and 
evenly.  No.  22  was  an  alloy,  golden  in  color,  very  close 
grained  and  with  a  fracture  in  all  respects  similar  to  No.  7, 
and  exceedingly  tough.  It  was  found  that,  when  the  average 
values  of  J/and  T  were  used,  No.  7  stood  first  upon  the  list, 
while,  when  the  higher  values  were  taken,  No.  22  was  first. 
In  the  case  of  No.  22  there  was  a  difference  in  the  values 
which  indicated  a  change  in  composition  either  from  volatili- 
zation or  from  some  other  cause.  No.  22  must  be  considered 
the  strongest  alloy. 

The  third  upon  the  list  is  No.  21.  It  exhibited  con- 
siderable liquation.  The  metal  was  of  a  bright  straw  color 
and  had  a  smooth,  regular  fracture  and  considerable  ductility. 
No.  5  was  fourth  and  No.  I  fifth.  No.  5  was  a  very  fine- 
grained alloy,  possessing  great  ductility  and  a  smooth,  square 
fracture  and  very  close  and  compact  grain.  Higher  results 
can  undoubtedly  be  obtained  from  an  alloy  of  this  composi- 
tion ;  these  specimens  showed  signs  of  slight  liquation. 

No.  i  was  a  tough  metal,  the  pieces  being  twisted  apart 
slowly,  snapping  suddenly,  as  in  the  previous  case ;  better 
results  should  be  expected  from  this  alloy ;  it  exhibited  signs 
of  an  imperfect  mixture  of  the  metals.  This  was  the  strongest 
alloy  reported  by  the  Author  previously.  The  sixth  position 
was  assigned  to  No.  11,  which  exhibited  a  fine  regular  fract- 
ure and  high  ductility  ;  it  twisted  apart  slowly  and  evenly. 
No.  1 8  was  a  good  alloy,  and  although  more  crystalline  than 
those  previously  mentioned,  had  a  smooth  fracture  and  high 
moduli ;  it  was  very  ductile.  The  eighth  upon  the  list,  No.  10, 
was  a  very  brittle  alloy ;  its  values  for  Br  being  but  4.6°  and 
8.8° ;  its  color  was  gray,  with  a  fracture  closely  resembling 
steel.  Its  tenacity  was  75,000  pounds  per  square  inch  (5,272 
kilogs.  per  sq.  cm.),  a  higher  figure  than  some  of  the  preced- 
ing alloys  have  given  ;  it  was  very  hard.  No.  4  stands  ninth. 
There  was  considerable  liquation  ;  while  it  exhibited  a  smooth 


STRENGTH  OF  KALCHOIDS.  445 

and  regular  fracture  and  broke  off  slowly  and  evenly.  It 
was  light  yellow  in  color.  Its  upper  end  was  granular  and 
uneven  in  fracture ;  it  was  of  a  very  light  gray  color,  indi- 
cating a  brittle  metal,  but  it  was  quite  strong  and  ductile. 
This  alloy  contained  I  per  cent,  more  zinc  and  I  per  cent, 
less  tin  than  No.  10,  and,  though  having  slightly  less  strength, 
it  was  far  more  ductile.  The  next  best  alloy,  No.  20,  an  alloy 
very  bright  in  color,  almost  white,  and  having  a  ragged  fract- 
ure, was  an  exceedingly  brittle  alloy,  its  average  value  for 
Br  being  but  6.8°  ;  its  tenacity  was  very  good.  The  eleventh, 
No.  1 6,  was  a  remarkably  dense  alloy,  very  hard,  with  a  fract- 
ure closely  resembling  steel.  Its  strength  was  very  great. 
No.  3,  the  twelfth  on  the  list,  was  less  brittle  than  the  pre- 
ceding, its  average  value  of  Or  being  1 1.9°.  While  testing  the 
A  end  a  "  set  "  took  place.  It  broke  suddenly,  giving  a  very 
ragged,  granular  fracture  ;  it  was  light  in  color.  Thirteenth, 
No.  17,  was  a  very  ductile  alloy,  its  values  for  6r  averaging 
48.6°.  It  was  of  a  deep  golden  color,  and  had  a  smooth, 
regular  fracture.  Fourteenth,  No.  19,  was  close-grained, 
brittle,  nearly  white  in  color,  and  gave  a  very  ragged  and 
uneven  fracture ;  it  broke  suddenly.  Fifteenth,  No.  9,  was 
another  very  brittle  alloy,  with  a  fracture  closely  resembling 
steel.  Sixteenth,  No.  6,  was  very  ductile,  giving  a  smooth, 
regular  fracture.  Its  values  of  tenacity  were  good.  Seven- 
teenth, No.  12,  was  not  a  triple  alloy,  as  it  contained  copper 
and  zinc  only.  It  was  an  exceedingly  beautiful  alloy,  of  a 
deep  golden  color  and  very  closely  grained.  This  was,  by 
far,  the  most  ductile  alloy  tested,  the  average  of  Br  being 
1133°.  Eighteenth,  No.  23,  was  the  second  most  ductile 
alloy.  This  alloy  had  a  fine  fracture,  smooth  and  regular. 
In  color,  it  very  closely  resembled  green  bronze.  Nineteenth, 
No.  13,  was  also  a  binary  alloy,  and  though  resembling  No. 
12  in  appearance  its  ductility  was  only  about  one-half  that 
of  No.  12.  Twentieth,  No.  15,  was  exceedingly  brittle,  and 
closely  resembled  steel  in  fracture.  Twenty-first,  No.  2, 
was  surrounded  by  alloys  which  gave  much  better  results, 
and  therefore  a  weak  specimen ;  this  was  not  looked  for  in 
this  place.  It  was  ductile  and  had  a  good,  even  fracture ;  it 


44-6    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

resembled  No.  23  in  color.  Twenty-second  and  twenty- 
third,  Nos.  8  and  14,  both  contained  large  amounts  of  zinc 
and  little  copper,  and  consequently  were  both  brittle  and 
weak. 

FIG.  29. — STRONGEST  OF  BRONZES. 


261.  Conclusions.  The  Strongest  Bronzes.— The  results 
obtained  from  this  investigation  are  well  exhibited  in  the  ac- 
panying  diagram,  Fig.  29.  It  was  concluded  that  the  alloy 
numbered  22  was  what  the  Author  has  called  the  "  strongest 
of  the  bronzes/'  and  that  its  composition  (Cu,  57;  Sn,  I  ;  Zn, 
42)  should  locate  the  peak  seen  in  the  model,  Fig.  25,  and  on 
the  map,  Fig.  24.  No.  5,  however  (Cu,  56 ;  Sn,  2  ;  Zn,  42), 
is  likely  to  prove  a  more  generally  useful  alloy  in  consequence 


STRENGTH  OF  KALCHOIDS.  447 

of  its  greater  ductility  and  resilience ;  and  alloys  with  a  little 
less  tin  may  often  prove  even  better  than  that.  The  Author 
has  called  the  compositions,  copper,  58  to  54;  tin,  y2  to  2^  ; 
zinc,  44  to  40,  which  may  be  considered  as  representative  of 
a  group  having  peculiar  value  to  the  engineer,  the  "maximum 
bronzes."  This  cluster  lies  immediately  around  the  peak  seen 
on  the  model,  Fig.  25,  including  the  point  of  maximum  alti- 
tude. The  safest  alloys  under  shock  are  those  containing 
the  smallest  quantities  of  tin. 

262.  The  Conclusions  reached  after  concluding  the  in- 
vestigations which  have  been  described  in  the  present  chap- 
ter are  confirmed  by  the  fact  that  a  number  of  single  compo- 
sitions have  been  independently  discovered  by  other  experi- 
menters, accidentally  or  incidentally  to  special  investigations, 
which  have  peculiarly  high  tenacity,  all  of  which  approximate 
more  or  less  closely,  in  their  proportions,  to  these  "  maximum  " 
bronzes  and  strongest  "  Kalchoids." 

Thus,  Mr.  Farquharson,  president  of  the  Naval  (British) 
Commission,  proposed,  in  1874,  an  alloy  composed  of  62  parts 
of  copper,  37  parts  of  zinc,  and  one  part  of  tin.  This  is  the 
reglementary  naval  alloy.  When  cast  in  bars  it  has  shown 
on  test  a  resistance  of  70,000  pounds  per  square  inch  (5,000 
kilogs.  per  sq.  cm.).  It  rolls  and  works  well,  can  be  hammered 
into  sheets,  and  is  fusible  only  above  red  heat.  It  may  be 
used  as  a  lining  for  engine-pumps.  It  is  but  slightly  oxidiz- 
able,  and  is  not  sensibly  attacked  by  sea  water,  as  shown  by 
experiments  with  it  extending  over  a  period  of  years.  A  slight 
loss  of  zinc  during  melting  must  be  taken  into  account.  The 
British  naval  bronze  for  screw-propellers,  stern  bearings,  bow- 
castings,  and  similar  work,  is  composed  of  copper,  87.65  ;  tin, 
8.32  ;  zinc,  4.03,  and  is  reported  to  have  a  tenacity  of  15  tons 
per  square  inch  (2,362  kilogs.  per  sq.  cm.),  and  to  average 
13^  tons  (2,126  kilogs.)  in  good  castings.  Tobin's  alloy,  al- 
ready described,  is  one  of  the  "  maximum  "  bronzes,  also, 
containing  copper,  58.22  ;  tin,  2.30;  zinc,  39.48.  Sterro-metal 
is  always  a  brass  of  nearly  the  same  proportions  of  copper  and 
zinc,  i.e.t  a  Muntz  metal,  containing  from  a  fraction  of  I  per 
cent,  to  sometimes  2  per  cent,  of  tin,  as  well  as  some  iron. 


448  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

The  bronze  used  for  journal  bearings  in  the  U".  S.  Navy 
contains  copper,  88 ;  tin,  10 ;  zinc,  2.  The  strongest  U.  S. 
copper-tin-zinc  alloy  is  that  discovered  by  Mr.  Tobin  and 
described  by  the  Author  in  earlier  articles,  and,  as  has  been 
stated,  had  a  tenacity  of  66,500  pounds  per  square  inch  of  origi- 
nal section,  and  71, 378  per  square  inch  of  fractured  area(4,575 
and  5,019  kilogrammes  per  sq.  cm.)  at  one  end  of  the  bar,  which 
was,  as  usual,  cast  on  end,  and  2  per  cent,  more  at  the  other. 
This,  like  the  "  maximum  alloy,"  was  capable  of  being  forged 
or  rolled  at  a  low  red  heat  or  worked  cold.  Rolled  hot,  its 
tenacity  was  79,000  pounds  (5,553  kilogs.  per  sq.  cm.),  and 
•when  cold-rolled,  104,000  (7,311  kilogs.).  It  could  be  bent 
double  either  hot  or  cold,  and  was  found  to  make  excellent 
bolts  and  nuts. 

These  and  other  compositions  which  have  been  occasion- 
ally introduced  as  having  extraordinary  strength  and  excep- 
tional value,  all  contain  a  small  amount  of  tin,  and  invariably 
fall  within  the  field  mapped  out  as  described  in  this  chapter 
as  that  containing  the  kalchoids  of  maximum  possible  strength. 
The  latter,  the  "  maximum  alloys,"  as  the  Author  has  called 
them,  will  probably  be  very  generally,  if  not  exclusively,  used 
when  alloys  are  required  of  peculiar  strength. 


CHAPTER  XII. 
STRENGTH  OF  ZINC-TIN  AND  OTHER  ALLOYS. 

263.  The  Zinc-Tin  Alloys  form  the  third  bounding  line 
of  the  system  of  copper-tin-zinc  alloys  which  have  been  stud- 
ied, as  the  copper-tin  and  copper-zinc  compounds  form  the 
two  sides  first  examined.  Within  the  field  represented  on 
the  map,  Art.  252,  page  425,  and  on  the  tin-zinc  side  of  the 
depression  which  lies  parallel  with  the  crest  of  maximum 
strength,  are  also  a  set  of  ternary  alloys  characteristically 
different  from  those  which  have  been  the  object  of  specia. 
investigation.  These  are  the  gray  and  the  white  alloys  of 
copper,  tin,  and  zinc,  which  have  no  use  in  the  work  of  the 
engineer  except  for  bearing  metals  and  as  solders.  The  char- 
acteristics and  uses  of  these  alloys  are  so  similar  to  those  of  the 
tin-zinc  alloys  that  they  are  here  classed  and  treated  of  together. 

The  zinc-tin  alloys  are  usually  easily  made,  and  are  sound 
and  dense  and  uniform  in  quality  and  structure.  They  are 
soft,  weak,  smooth  of  texture,  as  a  rule,  and  readily  alloy  with 
the  surface  coating  of  tin-plate  and  with  zinc;  they  thus  make 
good  "soft  solders  "  as  well  as  good  metals  with  which  to  line 
the  bearings  of  heavy  journals  in  heavy  machinery.  Common 
solders  are  elsewhere  described.  Among  them  are  "  yellow 
solder,"  composed  of  equal  percentages  of  copper  and  zinc, 
with  one  part  tin  either  added  or  substituted  for  two  or  three 
per  cent,  zinc ;  "  black  solder,"  composed  of  30  copper,  45 
zinc,  and  tin,  25  ;  these  fall  among  the  stronger  alloys  out- 
side the  gray  mixtures. 

No  tests  of  the  tin-zinc  alloys  were  made  in  the  research 
described  in  the  preceding  chapter,  but  the  study  of  the 
model,  Fig.  25,  page  427,  gives  the  value  of  this  set  of  com- 
pounds as  satisfactorily  as  if  they  had  all  been  directly  inves- 
tigated. 
29 


450  MATERIALS  OF  ENGINEERING—  NON-FERROUS  METALS. 

264.  The  Strength  of  Tin-Zinc  Alloys  is  seen  to  vary 
very  smoothly  and  uniformly  from  the  pure  zinc  to  the  pure 
tin  end  of  the  series.  It  may,  therefore,  be  assumed  as  sub- 
stantially true  that  the  strength  of  the  tin-zinc  alloys  is  the 
mean  of  that  of  their  constituents.  This  is  also  practically 
true  of  their  other  physical  and  mechanical  properties.  Hence, 
the  tenacity  of  good  alloys  of  this  class  should  be  expected  to 
be  not  far  from 


T  =  4,500  ^  +    ,,,  ,  6 

+  492 


in  British  and   metric   measures,  respectively,  where  t  and  z 
represent  the  proportion  of  each  metal  in  unity  of  weight. 

The  Resistance  to  Compression  is,  for  tin-zinc  alloys,  fairly 
taken  as  below,  for  ten  per  cent,  compression, 

C  —  6,000  t  +  20,000  z9\  ,    . 

Cm  -  422  t  +  1,406  z,       f 

The  Modulus  of  Rupture  maybe  taken  for  tin-zinc  com- 
positions, at 

R  =  3,500*  +  7,500*,) 

Rm  =  246  /  +  527  z,        f 

and  the  Modulus  of  Elasticity  at  7,000,000  British,  492,000 
metric  for  all.     The  Specific  Gravity  is  fairly  reckoned  at 

5.  G.  =  7-3  t  +  7.15*  .....     ....     (19) 

265.  The  Gray  Alloys  of  copper,  tin,  and  zinc  are  more 
uniformly  modified  by  the  addition  of  copper  to  the  tin-zinc 
compounds  than  are  the  yellow  and  stronger  alloys.  Those 
containing  little  zinc  are  very  irregular  in  strength,  but,  on 
the  whole,  weaker  than  those  containing  little  tin,  and  are 
generally  but  little  stronger  than  the  latter  metal.  These  cop- 
per-tin-zinc alloys,  rich  in  zinc  and  poor  in  tin,  are  strongest 
where  the  compositions  contain  between  copper,  15  or  20, 
zinc,  85  or  80,  and  are  weakened  quite  uniformly  by  the  ad- 
dition of  tin,  and  by  either  the  increase  or  diminution  of  the 


STRENGTH  OF  ZINC-TIN  ALLOYS.  45 1 

proportion  of  zinc,  the  tensile  strength  becoming  insignificant 
when  the  proportions  are  such  that,  approximately, 

z  4-  2  /  =:  90  per  cent., 

along  which  line  lie  the  alloys  of  maximum  hardness  and 
brittleness. 

The  tenacity  of  this  group  of  alloys  usually  ranges  be- 
tween 3,000  and  5,000  pounds  per  square  inch,  sometimes 
reaching  10,000  (211,  351,  703  kilogs.  per  sq.  cm.,  respectively); 
the  resistance  to  compression  is  not  known ;  the  modulus  of 
rupture  falls,  usually,  not  far  from  5,000  pounds  per  square 
inch,  rising  to  above  10,000  (352  and  703  kilogs.  per  sq.  cm.), 
and  as  often  falling  below  the  smaller  figure.  The  modulus 
of  elasticity  is  generally  about  12,000,000  (844,000  metric), 
although  with  the  softer  alloys  it  falls  to  one-half  that  amount. 

266.  Earlier  Investigations  of  these  alloys  have  been  of 
little  value  in  determining  their  properties.  An  alloy  of  tin, 
80;  zinc,  20,  is  said,  by  earlier  writers,  to  have  a  tenacity  of 
10,000  pounds  per  square  inch  (703  kilogs.  per  sq.  cm.),  or 
double  that  estimated  as  above.  The  alloy,  zinc,  77;  tin,  14; 
copper,  14;  antimony,  3;  lead,  I,  which  falls  into  the  class 
here .  considered,  very  nearly,  is  Burton's  alloy  for  plough- 
shares. Magee's,  for  the  same  purpose,  is  copper,  85  ;  tin,  12 ; 
zinc,  3.  Zinc,  20  ;  tin,  20,  is  Brayton's  alloy  for  eyelets.  Stru- 
bing's  anti-friction  metal  is  composed  of  zinc,  75;  tin,  18; 
lead,  4^2  ;  antimony,  2^.  The  alloy  composed  of  equal  parts 
tin  and  zinc  is  said  by  Laboulaye  to  be  remarkably  durable 
under  wear,  and  to  have  nearly  the  strength  of  brass,  a  state- 
ment which  is  not  confirmed  by  the  investigations  here  de- 
scribed and  requires  confirmation.  The  strength  of  many  of 
these  alloys  has  never  been  determined. 

An  "anti-friction  metal,"  of 'unknown  composition,  tested 
by  the  Author,  had  a  tenacity  of  11,100  pounds  per  square 
inch  (773  kilogs.  per  sq.  cm.),  and  broke  without  stretching. 

An  alloy  of  gold,  14;  silver,  10,  with  a  trace  of  copper,  is 
often  made  into  wire  to  replace  brass,  and  is  found  to  have 
about  the  same  strength. 


45 2   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Various  alloys  examined  by  Muschenbroek,*  who  was  the 
only  physicist,  or  engineer,  who  had  given  much  time  to  the 
study  of  the  mechanical  properties  of  alloys  until  a  very 
recent  period,  were  found  to  have  tenacities  as  given  in  the 
following  table  to  the  nearest  thousand. 

TABLE  LXXXI. 

TENACITY   AND   DENSITY   OF   VARIOUS   ALLOYS. 


ALLOYS. 

TENACITY. 

S.  G. 

Lbs.   per 
sq.  in. 

Kilogs.  per 
sq.  cm. 

Gold,                66.7;  Silver,          33.3  

28,000 

1,968 

83.3;  Copper,       16.7  

50,000 

3,515 

.  .  . 

Silver,              83.3;       "              16.7.... 

49,000 

3,445 

.  .  . 

80.0;  Tin,             20.0  

41,000 

2,882 

.  .  . 

Ti 

n  (Eng.),     90.9;  Lead,             9.1  

7,000 

492 

... 

1 

' 

88.9;                       ii.  i  

8,000 

562 

.  .  . 

• 

1 

85.7;                       I4-3-..- 

8,000 

562 

... 

1 

4 

80.0;                     20.  o.  .  .  . 

II,OOO 

773 

.  .  . 

* 

* 

66.7;                     33.3.  ... 

7,000 

492 

4 

' 

50.0;                     50.0  

7,000 

492 

T 

n  (B 

nca),  90.9;  Antimony,    Q.I.... 

11,000 

773 

7*36 

* 

88.9; 

ii.  i  

10,000 

703 

7.28 

* 

85.7; 

14.3..-. 

13,000 

914 

7-23 

* 

80.0; 

20.  o.  .  .  . 

13,000 

914 

7.19 

' 

66.7; 

33-3-.  •• 

12,000 

.  874 

7.II 

* 

50.0; 

50.0  

3,OOO 

211 

7.06 

T 

n(B 

nca),  90.9;  Bism 

uth,       9.1  

13,000 

914 

7-58 

' 

80.0; 

20.  o.  .  .  . 

8,000 

562 

7.6l 

' 

66  7; 

33-o.... 

14,000 

984 

8.08 

* 

50.0; 

50.0  

12,000 

844 

8.15 

< 

33-3; 

66.7.... 

10,000 

703 

8.58 

* 

20  o; 

80.0  

8,000 

562 

9.01 

' 

Q.I; 

90.9.... 

4,000 

281 

9.44 

L 

ad,                50.0;  Bisrr 

uth,     50.0.  .  .  . 

7,000 

492 

10.93 

66.7; 

33-3.... 

6,000 

422 

11.09 

9.1; 

90.9.... 

3,000 

211 

10.83 

267.  The  Records  of  Experiments  upon  the  copper-tin- 
zinc  alloys  which  follow  are  selected  from  those  reported  by 
the  Author  to  the  Committee  on  Alloys  of  the  U.  S.  Board 
as  representative  of  the  more  successful  mixtures.  These 
alloys  have  been  already  described  at  some  length,  and  further 

*  Introd.  ad  Phil.  Nat.;  Phil.  Ma^.,  1817,  Vol.  L.;  Tredgold. 


STRENG  TH  OF  COPPER-ZINC-  TIN  ALLO  VS.  45  3 

description  in  detail  is  here  unnecessary.*  Although  selected 
examples,  some  considerable  part  of  the  variation  observed 
among  them  is  probably  due  to  the  varying  conditions  met 
with  in  ordinary  foundry  work;  the  principal  cause  of  these 
great  differences  of  strength  and  ductility  is,  however,  to  be 
attributed  to  differences  in  composition.  It  will  be  observed 
that  the  strongest  of  these  alloys  are  not  distinguished  by 
great  ductility,  a  fact  already  frequently  illustrated  in  earlier 
portions  of  this  work. 

Examining  the  records  of  test  by  tension,  it  is  seen  that 
the  better  class  of  alloys  exhibit  a  great  regularity  of  elonga- 
tion under  increasing  loads.  Comparing  the  tenacities  of  the 
best  specimens  with  the  moduli  of  rupture,  it  is  seen  that  the 
latter  exceed  the  former  by  about  fifty  per  cent.  In  ductile 
metals  the  resistances  to  compression  and  to  extension  do 
not  greatly  differ  where,  as  in  a  bent  bar  of  the  proportions 
here  adopted,  the  compressed  metal  is  not  confined.  The 
modulus  of  rupture  for  a  beam  of  rectangular  section  when 
the  material  is  elastic  and  brittle  is  that  given  in  the  common 

theory  of  resistance  of  materials,  R  =  -T~TJ,  in  which  M,  b,  d, 
are  the  bending  moment,  the  breadth  and  the  depth  of  the 


bar.     When   the   material   is   ductile,  R^  =  ^—r,   and,  there- 

oa* 

fore,  R  =  |  Rj  when  the  bar  is  of  the  same  dimensions  and 
the  same  bending  moment  is  attained  at  rupture,  assuming 
the  same  theory  applied  to  each  case  and  the  apparent  mod- 
ulus to  be  accepted.f 

In  the  cases  of  some  of  the  valuable  alloys  of  which  the 
records  of  test  are  here  given,  the  moduli  of  rupture  are  often 
in  excess  of  the  tenacities  by  fifty  per  cent.,  or  in  the  same 
proportion  as  in  wrought  iron,J  proving  them  to  belong  to  the 
class  to  which  the  second  of  the  expressions  just  given  be- 
longs. This  is  best  illustrated  by  bar  No.  12  (copper,  58.22  ; 
tin,  2.30;  zinc,  39.48). 

*  Vide  Report  of  the  U.  S.  Board,  Vol.  II.,  Washington,  1881. 
f  Part  II.,  p.  487,  §  263,  Eq.  (113). 
J  Part  II.,  p.  491. 


454  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE  LXXXII. 
TESTS  BY  TENSILE  STRESS. 

ALLOYS    OF    COPPER,    TIN,    AND    ZINC. 

DIMENSIONS. — Length  =  5"  (12.7  cm.);  diameter  =  .798"  (2  cm.). 

BAR    NO.    I    B-D. 

COMPOSITION. — Original  mixture :  Cu,  70 ;  Sn,  8.75  ;  Zn,  20.25. 


K 

tt 

M 

gg 

H 

C£ 

Sa 

1- 

. 

H 
Z  O 

1  - 

-1 

M 

O 
« 

SET. 

11 

«5 

i 

SET. 

l3 

£  S 

o 

S° 

£2 

P 

< 

Q 

z 

O  (4 

Q 

o 

O  f-' 

3 

3 

a 

P 

3 

3 

a 

Z  z 

3  " 

Pounds. 

/wA. 

Inch. 

Pounds. 

Inch. 

Inch. 

1,400 

.OO3I 



.002 

16,000 

.0046 

.092 

i,  600 

.0001 

.OO2 

18,000 

.0052 

.104 

i,  800 

.0002 



.004 

20,COO 

.006! 

.122 

2,000 

.0002 

.004 

3~o 



.0001 

.OO2 

2,500 

.0003 



.006 

10,000 

.0010 

.020 

3,000 

.0004 



.008 

20,000 

.0053 

.  .    .  . 

.106 

3i5°° 

.0005 

.010 

22,OOO 

.0064 

..    .. 

.128 

4,000 

.0007 



.014 

24,000 

.0084 

.  . 

.168 

5,000 

.0009 



.018 

28,OOO 

.0142 

.284 

6,000 

.0012 



.024 

32,000 

.0217 

•434 

7,000 

.0014 



.028 

36,000 

.0316 

.  .   .  . 

.632 

8,000 

.00l6 

.032 

Broke. 

9,000 
10,000 

11,000 

12,000 
13,000 

.OO22 
.0024 
.0028 
.0031 
0035 

••••• 

.044 

.048 

.056 

.062 
.070 

Tenacity  per  square  inch,  original  section, 
36,000  pounds  (2,531  kilogs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  section, 
36,080  pounds  (2,536  kilogs.  per  sq.  cm.). 
Diameter  of  fractured  section,  0.797"  (2  cm.). 

14,000 

.0038 



.076 

BAR    NO.   5    B-D. 

COMPOSITION. — Original  mixture:  Cu,  88.135  5  Sn,  1.865  ;  Zn,  i< 


3,200 

.0014 

-035 

7,000 

.0040 

.100 

4,000 

.0018 

-045 

8,000 

.0042 



.105 

4.500 

.0020 

.050 

9,000 

.0044 

.  no 

5,000 
5,5°o 

.0023 
.0026 

::::: 

.057 

.065 

10,000 

11,000 

.0050 
.0054 

•  125 
.135 

6,000 

.0028 

.070 

12,000 

.0058 

.145 

7,000 
8,000 

.0033 

.0036 



.082 
.090 

13,000 

14,000 

.0088 
.0121 

.220 
-302 

9,000 

.0039 

.097 

15,000 

.0161 

.402 

10,000 

.0043 

.107 

16,000 

.0252 

.630 

11,000 

.0047 



.117 

18,000 

.0548 



I-37° 

12,000 

.0052 

.130 

20,000 

.0987 

2.460 

300 

.0008 

22,000 

•  *5<)5 

3-987 

100 

.OOII 

.027 

26,000 

.3118 



7-795 

1,400 

.0013 



.032 

30,000 

•  5177 

12.942 

1,  800 

.0015 



.037 

33,000 

.7818 

19-545 

2,200 

.0017 

.042 

Broke. 

2,600 

3,000 
4,000 
5,000 
0,000 

.0019 

.0022 

.0028 
.0033 
.0037 



.047 
•055 
.070 
.082 
.092 

Tenacity  per  square  inch,  original  section, 
33,000  pounds  (21.30  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  section, 
47,649  pounds  (33.52  kgs.  per  sq.  cm.). 
Diameter  of  fractured  section,  0.664"  U-7  cm.). 

STRENGTH  OF  COPPER-ZINC-TIN  ALLOYS. 


455 


TABLE   LXXXII.— Continual. 

BAR   NO.  7   B-D. 

COMPOSITION. — Original  mixture:  Cu,  66.885;  Sn,  1.865;  Zn,  31.25. 


2  fc 

H 

2  h 

• 

-  O 

-  O 

D 

D 

. 

C* 

2* 

2  t~ 

O1 

Jr 

2  ^"* 

K  5 

i 

SET. 

ggg 

£5 

p 

SET. 

-  P  a 

a.  — 

s 

g  «§ 

£  2 

O 

0  °  ^ 

O 

z 

D 

•£  £•  2 

3 

-" 

a 

_I 
M 

1  r 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

300 





.... 

6,000 

.0029 

.058 

1,000 

.0002 

.004 

8,000 

•0033 

.066 

2,000 

.0004 



.008 

10,000 

.6042 



.084 

3,000 

.0006 

.OI2 

12,000 

•0055 

.110 

4,000 

.0008 

.Ol6 

14,000 

.0069 

..... 

.138 

4,200 

.0008 



.Ol6 

l6,OOO 

.0089 



.178 

4,400 

.0009 



.018 

l8,000 

.0113 

.226 

4,600 
5,000 

.0010 

.0011 

:::.: 

.020 
.022 

2O,OOO 
22,000 

.0209 
.0309 



.418 
.618 

5,400 

.0012 

.024 

24,000 

.0444 

.888 

6,000 

.0013 

.026 

26,000 

.0589 



1.178 

7,000 

.0015 



.030 

28,000 

.0779 

1.558 

8,000 

.0017 

.054 

30,000 

.1019 

2.038 

9,000 

.OO22 



.044 

32,000 

•  1391 



2.782 

11,000 

.OO29 

.058 

34,000 

.1171 

2.342 

12,000 

.0036 



.072 

36,000 

.2181 

4.362 

14,000 
15,000 
16,000 
17,000 
300 

2,OCO 

.OO5O 
.0060 

.0082 
.OO2O 

.0016 

.100 

.120 

.140 

.164 
.032 

.040 

36,540       Broke. 
Tenacity  per  square  inch,  original  section, 
36,540  pounds  (24.68  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  section, 
41,028  pounds  (28.84  kgs.  per  sq.  cm.). 
Diameter  of  fractured  section,  0.753"  (1.9  cm.). 

4,000 

.0025 



.050 

BAR   NO.  12    B-D. 

COMPOSITION. — Original  mixture  :  Cu,  58.22  ;  Sn,  2.30;  Zn,  39.48. 


T00 

30,000 

.0240 

.48 

1,OX> 

.0012 

.... 

.024 

32,000 

•  0254 

.=08 

2,000 

.OO22 

.044 

34,000 

.0268 

..... 

.536 

2,2OO 

.0024 

...     - 

.048 

36,000 

.0282 

•  564 

2,400 

.0026 

.... 

.052 

3<3,ooo 

.0297 



•  594 

2,600 

.0028 

.056 

40,000 



.626 

2,800 

.0030 

.060 

300 

.0:50 

.030 

3,000 

.0032 

.064 

10,000 

.C2I5 

•43° 

3,200 

.0034 

.... 

.068 

20,000 

.0279 



.558 

3.4°° 

.0036 

.072 

30,000 

.0345 



.690 

3,600 

.0038 

.076 

40,000 

.0299 



.798 

3,800 

.0041 

.082 

42,000 

.0423 

•846 

4,000 

.0044 

.088 

44,000 

.0447 

.894 

5,000 

•0054 

.108 

46,000 

•  0473 



.946 

6,000 

.0064 

.128 

48,coo 

.0494 



i'^ 

7,000 

.0074 

.148 

50.000 

.0527 

8,000 

.Oo8l 

.162 

52,000 

.0568 



.136 

9,000 

.0098 

.... 

.176 

.0615 

•23 

10,000 

.0085 

.190 

56,000 

.0674 



•  348 

300 

.0022 

.044 

58,000 

.0771 



•542 

10,000 

.0113 

.... 

.226 

60,000 

.0873 

.746 

12,000 

.0125 

25 

62,000 

.0958 



.916 

14,000 

•0137 

.274 

64,000 

.1277 

•554 

l6,OOO 

.OI5O 

.30 

66,000 

•  1577 

3.154 

l8,000 

.0165 

•33 

67,000 

Broke. 

20,000 
22,OOO 
24,000 

.0176 
.0189 
.0202 

•352 
-378 
.404 

Tenacity  per  square  inch,  original  section, 
67,600  pounds  (47.52  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  section, 

26,000 
28,000 

•0213 
.O226 

.426 
•452 

73,160  pounds  (51  43  kgs.  per  sq.  cm.). 
Diameter  fractured  section,  0.767"  (1.9  cm.). 

456  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE   LXXXIL— Continued. 

BAR   NO.  40   B. 

COMPOSITION.— Original  mixture  :  Cu,  50;  Sn,  5  ;  Zn,  45. 


u 

Z   fe 

w 

2  fc 

« 

«  O 

K 

-  O 

£> 

3 

z 

Z  £ 

ST.. 

z 

Z  £ 

ii 

I 

SET. 

|8jj 

£2 

P 

SET. 

H  8  jij 

Q 

Z 

Z  *  Z 

Q 

z 

2  K  Z 

c3 

3 

3*2 

3 

3 

j  a,  J 
W 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

300 





.... 

14,000 

.0126 

.252 

1,000 

.0009 

.018 

16,000 

.0141 



.282 

2,000 

.0018 

.036 

18,000 

.0155 

.310 

2,500 

.0022 



.044 

20,000 

.0169 



.338 

3,000 

.0025 

.050 

300 

.0005 

3:500 

.0028 

.056 

1,000 

.0013 

4,000 

.0022 

.064 

22,000 

.0184 

.368 

300 

.0000 

24,000 

.0195 

'39° 

1,000 



.0009 

26,OOO 

.0205 

.410 

4,000 

.0032 

!o64 

28,000 



.0215 

•  430 

6,000 
8,000 

10,000 

300 
1,000 

10,000 

12,000 

.0051 
.0069 
.0087 

.0092 
.0107 

.0002 

.0011 

.102 
.138 
.174 

.214 

3O,OOO                     .O225                      .450 

31,300       Broke. 
Tenacity  per  square  inch,  original  section, 
31,300  pounds  (22.00  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  section, 
31,300  pounds  (22.00  kgs.  per  sq.  cm.). 
Diameter  of  fractured  secUon,  0.798"  12  cm.). 

BAR  NO.  52  B. 

COMPOSITION.— Original  mixture  :  Cu,  60  ;  Sn.  5  ;  Zn,  35. 


300 

300 

.0007 

1,000 

.0006 



.012 

20,000 

0092 



!i84 

2,000 

.0018 

.036 

22,000 

0098 

.196 

2,500 

.0023 



.046 

24,000 

0105 



.210 

3,OOO 

.0026 

.052 

26,000 

0114 



.228 

3,500 

.0030 

.060 

28,000 

0125 

.250 

4,000 

.0033 



.066 

30,000 

0138 



.276 

300 

.00005 

300 

.0026 

.... 

1,000 

.0006 

.... 

30,000 

0144 

4,000 

.0027 



.... 

32,000 

0153 



:3o6 

6,000 

.0035 

.070 

34,000 

0165 

.330 

8,000 

.0046 



.092 

36,000 

0182 

.364 

10,000 

.0054 



.108 

38,000 

0199 

.398 

300 

.0001 

38,330    1  Broke. 

10,000 
12,000 

14,000 

16,000 
18,000 

.0019 
.0058 
.0068 

.0076 
.0083 

.'ii6 

.136 

.152 
.166 

Tenacity  per  square  inch,  original  section, 
38,300  pounds  (26.95  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  section, 
38,534  pounds  (24.84  kgs.  per  sq.  cm.). 
Diameter  of  fractured  section,  0.797"  (2  cm.) 

20,000 

.0090 



.180 

STRENGTH  OF  COPPER-ZINC-TIN  ALLOYS. 
TABLE   LXXXII.— Continued. 

BAR   NO.  59   A. 

COMPOSITION.-  Original  mixture  :  Cu,  70 ;  Sn,  5  ;  Zn,  25. 


457 


1 

2£ 

w 
< 

ss 

g 

2- 

2  H 

0- 

2 

1$ 

H 

SET. 

pi* 

K  u 

O 

B 

SET. 

§§  . 

a 

1 

1«1 

Q 

1 

isi 

a 

H 

s£3 

s 

u 

fl 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

300 



300 



.0004 



1,000 

.0004 

.... 

.008 

20,000 

•0133 

.  .  .  .  • 

2,000 

.0009 



.018 

22,000 

.0171 

.  r.  .  . 

.342 

2,500 

.0012 

.024 

24,000 

.0233 

..... 

.466 

3,000 

.OOI4 

.... 

.028 

26,000 

.0296 

.596 

3,500 

.00l6 

.032 

28,000 

.0376 



.752 

4,000 

.00l8 

.... 

.036 

30,000 

.0472 



.944 

300 

0000 

300 

.0078 



1,000 

0004 

.... 

30,000 

.0470 

.  .  .  .  * 

..... 

4,000 

.00l8 

.... 

32,000 

.0517 

1.034 

6  ooo 

.0023 

.046 

34,000 

.0684 

1.368 

8,000 

.OO29 

.... 

.058 

36,000 

.0838 



1.676 

10,000 
10,000 

12,000 

14,000 
16,000 
18,000 

.0036 

.0038 
.0046 
.0059 
.0079 
.0098 

OOO2 

.072 
.092 

.118 

.158 

.196 

38,000              .1028?               2.056 
Broke  just  after  reading  was  taken. 
Tenacity  per  square  inch,  original  section, 
38,001  pounds  (26.61  kgs.  per  sq.  cm  ). 
Tenacity  per  square  inch,  fractured  section, 
39,014  pounds  (27.43  kgs.  per  sq.  cm.). 
Dfameter  of  fractured  section,  0.788"  (2  cm.). 

20,000 

.0129 

— 

.258 

BAR  NO.  67  A. 

COMPOSITION.— Original  mixture :  Cu,  80 ;  Sn,  5  ;  Zn,  15. 


300 

20,000 

.0632 

1.264 

1,000 

.0012 

.... 

.024 

300 

..... 

.0518 

...... 

2,000 

.0027 

•054 

2O,OOO 

.0638 



2,500 

.0036 

.072 

22,OCO 

.0847 

1.694 

3,000 

.0044 

.... 

.088 

24,COO 

.1150 



2.300 

3i5°° 

.0050 

.  TOO 

26,OOO 

.1582 

3.164 

4,000 

.0056 

.112 

28,000 

.2650 



4.  ioc 

300 



0003 

30,000 

.2642 



5.284 

4,000 

.0059 

3CO 

.2502 

5.004 

5,000 

.0069 

.... 

.138 

30,000 

.2682 



5.364 

6,000 

.008I 

.... 

.162 

32,000 

.3422 



6.844 

8,000 

.0111 

.222 

34,000 

.4127 

8.254 

10,000 

.0150 

.... 

.300 

36,000 

.5022 



10.044 

300 



0038 

37,500 

.5804 



II.  608 

1,000 

0052 

.    .    .    • 

Broke. 

10,000 

12,000 
14,000 
l6,OOO 
18,000 

•OI57 
.0198 
.0271 
.0346 
.0469 

•542 
.692 
.938 

Tenacity  per  square  inch,  original  section, 
37,560  pounds  (26.40  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  section, 
48,905  pounds  (34.38  kgs.  per  sq.  cm.). 
Diameter  of  fractured  section,  o.  700"  (i  .78  cm.). 

MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE  LXXXII.—  Continued. 

BAR   NO.  73   A. 

COMPOSITION.— Original  mixture :  Cu,  55  ;  Sn,  0.5  ;  Zn,  44.5. 


w 

Q 

o  H* 

w 

Q 

Q     rj 

K 

<; 

K 

Z    c/) 

^  "Z 

<; 

D 

a 

CJ      • 

W 

D 

a 

(J    • 

H 

""a; 

•z  u 

c  z 

§«S 

0  g 

-a 

o  5 

2w[j 

O  H 

£2 

p 

§»s 

~>  H 

S5 

I2 

S3 

J  h 

o 
jj 

H 

sis 

w 

Q 

g 

Q 

3 

P 

s£§ 

M 

Q 
O 

Pounds. 

Inch. 

Pounds. 

Inch. 

300 

36,000 

.O473 

Q4.6 

1,000 

.00025 

.005 

38,000 

.0586 

I  .  172    !     

2,000 

.00065 

.013 

15,383,076 

40,000 

.0748 

1  .  496 

2,673,796 

3,OOO 

.001  1 

.022 

13,636,363 

300 

Set  .05535 

Set  1.107 

4,OOO 

.00155 

.031 

12,903,258 

40,000 

.07815 

j  563  |   

5,000 

.00195 

.039 

12,820,512 

42,000 

.09025 

1.805  |   

6,000     !            .0024. 

.048 

12,500,000 

44,000 

.  IIQ7 

2    304 

7,000 

.00295 

•059 

11,868,474 

46,000 

•*393 

2.786     

8,000 
9,000 

.0035 
.0038 

.070 
.076 

11,428,571 
11,842,105 

48,000 
50,000 

.16255 
.2006 

3-251 
4.014 

1,245,762 

10,000 

.0042 

.084 

11,904,761 

52,000 

.2259 

4-518  I  ......... 

3OO 

Set  .00005 

Set  .001 

3OO 

Set  .  19825 

Set  3.965 

10,000 

.0042 

.084 

52,000 

•22955 

4-591 

12,000 

.0052 

.104 

11,538,461 

54,000 

.26605 

5-321 

14,000 

.0062* 

.120 

11,200,000 

56,000 

.29875 

5-975 



16,000 

.0072 

.144 

n,  in,  in 

58,000 

.3263 

6.526 

18,000 

.0082 

.164 

10,975,668 

60,003 

.3720 

7  440 

20,000 
300 

.0089^ 
Set  .00055 

Set  !on 

11,172,184 

300 

60,000 

Set  .3496 

Set  6.992 

20,000 

.0095 

.190 

62,000 

'4636 

9272 

22,000 

.0109 

.218 

10,009,082 

64,000 

.4714 

•*/*          

9.428     

24,000 

26,000 
28,000 

300 

28,000 
30,000 

.01265 
.01485 
.0178 
Set  .00515 
.01815 
.02235 

•  253 
.297 
c       -356 
Set  .103 
.363 
•  447 

9,494,07! 
8,755,555 
7,865,168 

68,900       Broke. 
Tenacity  per  square  inch,  original  section, 
68,900  pounds  (48.44  kgs.  per  sq.  cm.). 
Tenacity  per  square  inch,  fractured  section, 
92,136  pounds  (64.77  kgs.  per  sq.  cm.). 
Diameter  of  fractured  section,  .6900"  (1.75 

32,000 

.02755 

cm.). 

34,000 

.03625 

.725 

STRENGTH  OF  COPPER  ALLOYS. 


459 


TABLE    LXXXIIL 
TESTS  BY  TRANSVERSE  STRESS. 

ALLOYS   OF   COPPER,    TIN   AND   ZINC. 

DIMENSIONS. — Length,  1=22"  (5588  cm.);  breadth,  b  =  i.oo"  (2.54  cm.); 
depth,  d=  i.oo"  (2.54  cm.). 

BAR   NO.  I. 

COMPOSITION.— Original  mixture :  Cu,  70 ;  Sn,  8.75  ;  Zn,  21.25.    Analysis :  Cu,  70.22  ;  Sn,  8.90 ; 

Zn,  20.68. 


LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
36 

10 
20 

£ 

80 

IOO 
120 

160 

2OO 
10 

3 

200 

240 

280 

320 

360 
400 

10 

4 

400 

44° 
486 
520 

1^ 
600 

IO 

60! 

640 

680 

g 

800 

IO 

800 
840 
880 

& 

1,000 

Inch. 

.0004 
.0018 
.0067 
.0125 
.0172 
.0215 
.0250 
.0287 

•0359 

•°437 

•0435 
.0500 
.0568 
.0635 
.0702 
.0764 

.0764 
.0825 
.0891 
.0960 

.1022 
.1086 

:ios; 

."57 
-1234 
.1305 
.1380 
.1468 

^464 
•'549 
.1627 
.1716 
.1808 
.1905 

Inch. 

Pounds. 

10 

Left  10  nr 
resista 

I.OOO 

Left  und 
Resistan 
Resistan 
Resistan 
1,000 

1,010 
1,020 

1,040 
1,  060 
1,  080 

1,120 

1,160 

1,200 

1          '3 
Resistan 

Decrease 
,200 
,240 
,280 
030 
,360 
1,400 

10 

3 

10 

1,400 
1,440 
1,480 
1,520 
1,550 
ringing 
Breaking 

Modulus 
metric) 

Inch. 

lin.  ;  showec 
ice. 

er  strain. 
:e  diminishee 
:e  diminishec 
:ediminishec 
.1951 
.1967 
.1994 
•2033 
.2081 
.2145 
.2259 
•  2373 
•  2515 

:e  increased 

of  set,  .0004 
•  2536 
.2634 
.2785 
.2962 
-3*43 
•3351 

335i 
.35i6 
.3713 
.4019 
Broke  sud< 
sound. 
load,/>=i, 

of  rupture,  1 

Inch. 
.0132 
.0098 
very  slight  i 

ncrease  of 

.0018 
.0003 

.0050 

.OOOQ 

7,820,389 
8,383-437 
9,138,945 

9>748,i66 
10,498,644 
i°,953,995 
11,948,989 
11,990,718 

I  in  5  min.  to 
1  in  20  min.  t 
in  i  hr.  55  m 

996  Ibs. 
o  990  Ibs. 
.  to  985  Ibs. 

12,575,185 
12,914,657 
13,202,297 
13,434,278 
13,716,389 



.0291 
.0161 
n  20  min.  to 
.0257 

12,500,184 

9  Ibs.'  " 

.0054 
.0001 

.0056 
.0026 

13,972,399 
14,113,565 
14,190.748 
14,355,235 
14,474,203 

.0721 
.0681 
.0697 

10,945,277 

^,491,715 
14,436,664 
14,454,236 
14,428,053 
14,277,003 

[enly  in  middle,  with 
550  Ibs. 

?  =  ^  =  50,541  (3,553 

'.'.'.'.'. 

14,206,957 
14,169,948 
14,045,709 
13,910,603 
13,752,39° 

460  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


TABLE  LXXXIII.—  Continued. 


COMPOSITION.—  Original  mixture  :  Cu,  88.135  ;  Sn,  1.865  ',  Zn,  10.    Analysis:  Cu, 
89.50;  Sn,  2.07  j  Zn,  8.11. 


LOAD. 

2: 

o 

u, 
w 
g 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
3 

10 

20 

£ 

80 

100 
120 

160 

200 
IO 

3 

200 
240 
280 
320 
360 
400 
10 

3 
400 
440,  beam  s 
480 
520 
560 
600 

10 

Left  unde 
Resistanc 

Inch. 

.0018 
.0071 
.0119 
.0162 
.0190 
.0224 
•  0255 
.0314 
•0379 

.0436 
.0511 
.0584 
.0658 
•  0727 

•  °749 
nks.  .0830 
.0921 
.1086 
.1309 
.1631 

.1695 
r  strain, 
e  diminished 

Inch. 

Pounds. 
Resistan 
Resistan 
600 
620 
640 
680 
720 
760 
800 

IO 

3 
800 
840 
860 
880 
900 
920 
940 
960 
980 

1,000 
1,020 
1,040 
I,o6o 
I,  080 
1,  100 
1,120 

Bar  ren 
Breakin 

Moduli, 
(metri 

Inches. 
ce  diminishe 
ce  diminishe 
.1749 
.1854 

•  5394 
.6984 

.7154 
.9199 

.    -9859 
.1389 
.26 
•36 
.56 
•74 
.92 

.  12 
•32 
•52 
.72 
.92 
3-27 
3.67 

loved, 
j  load,  />-=!, 

s  of  ruptur 
:,  2,250). 

Inch. 
i  in  4  min.  tc 
i  in  41  min. 

>  578  Ibs. 
.0  570  Ibs. 

.0101 

.0059 

5,325,416 
6,354,696 

7,001,935 
7,960,094 
8,439,831 
8,896,573 
9,633,235 
9,976,370 

JesJ 

2,164,546 

.02:14 
.0162 

.0849 
.0820 

10,359,026 
10,359,028 
10,343,283 
10,401,776 

—  

'.'.'.'.'.'.'.'.'. 

10,022,046 
9,852,884 

6,954,660 

t2o  pounds 

*,  ./?  ^^  •  •- 

.«- 

in  i  min.  to  584  Ibs. 

BAR   NO.    7. 

COMPOSITION.— Original  mixture  :  Cu,  66.885  ;  Sn,  1.865  ;  Zn,  31.25. 


3 
10 

20 

40 
80 

120 

160 

200 
IO 

3 

200 
240 
280 
320 
360 
400 
10 

3 

400 


.0060 
.0041 


.0091 
.0066 


9,699,400 
9,359,172 
10,616,259 

",390,754 
11,628,705 

">934,387 


12,478,758 
",385,635 
12,589,165 
12,837,309 
12,839,159 


440 
480 
520 
560 
600 


^ 


.0920 

.1012 
.1109 
.1239 
.1402 


M33 


Beam  sinks. 


.0257 
•0233 


12,651,391 


11,415,131 


Left  under  strain. 
Resistance  diminished  in  3  min.  to  596  Ibs. 
Resistance  diminished  in  10  min.  to  594  Ibs. 
Resistance  diminished  in  16  h.  15111.  to  581  Ibs. 

i°      I        .0290       I  

_    ,    3       I         ..,..  .0274         |  

Left  under  strain. 

Resistance  increased  in  10  min.  to  5  Ibs. 

.0273 
[400 
1440 


STRENGTH  OF  COPPER  ALLOYS. 
TABLE   LXXXIII.  (Bar  No.  7).—  Continued. 


461 


LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
620 
640 
680 

% 

% 

800 

10 

3 

8d 

840 
880 
920 
960 

1,000 
10 

3 

1,000 

Inch. 

.1496 

.1575 

.1836 

.2128 
.2642 

.3069 
.3099 

.3471 

.4296 
-5156 
.6145 

•  7"7 
.7169 

Inch. 

Pounds. 
1,040 
j      1,080 

1,120 

1,160 

1,200 

1,240 

1,280 

1,320 
1,360 
1,400 
1,440 
1,480 
1,500 

3 
Bar  remc 
Breaking 

Modulus 
(metric, 

Inches. 

•779Q 
.9498 
1-0549 
1.19 
J-37 
'•57 
J-73 
1.93 
2.13 

2.33 
2.61 

3-" 
3-76 

Inches. 

^387 
•  1343 
•  1334 

6,952,976 



3-32 

00. 

?-!^  = 

zbdi 

49.599 

>ved. 
load,  P=  i  ,5 

of  rupture,  A 
3»4i7>- 

:£i 

3,747,836 

BAR  NO.    12. 

COMPOSITION. — Original  mixture:  Cu,  58.22  ;  Sn,  2-30;  Zn,  39.48. 


3 

10 
20 

£ 

120 

160 

200 
JO 

3 

200 
24O 
280 
320 
360 
400 
10 

3 
400 

£ 

520 

£ 

10 

*i 

& 

720 
760 
800 

.0024 
.0046 
.0093 

.0202 
.0296 
.0418 
.0517 

•0532 
.o6l2 
.0712 
.0802 
.0908 
.1000 

.1010 

.1095 

•"97 
.1294 
.1403 
.1511 

•'SiS 
.1629 
.1740 
.1846 
.1944 
.2038 

10 
*2 

840 
880 
920 
960 
1,000 
10 

3 

1,000 

1,040 
1,080 

1,120 

1,160 

1,200 
10 

3 

1.200 

Left  und 
Resistanc 
1,240 
1,280 
1,320 
',360 
1,400 

10 

3 
1,400 
1,440 
1,480 
1,520 

'.2028 
.2142 
.2247 
•2344 
•2433 
2550 

^2544 
.2642 
.2764 
.2847 
.2951 
.3062 

306^ 
sr  strain. 

:e  dimmishec 
.3170 
.3276 
•  3398 

1" 
& 

•3959 
.4102 

•0043 
.0032 

.0032 

.0011 

11,760,504 
11,040,471 
",7'2,535 
10,965,874 

10,353,743 
10,463,891 

:oo64 

.0046 

10,607,511 

IQ.593,349 
10,616,562 
10,672,909 
10,607,511 

!ooo8 

10,607,511 
10,637,306 
10,792,679 
10,724,336 
10,819,661 

.0114 

•0093 

10,647,661 
10,569,132 
10,641,044 
10,632,674 
10,600,509 



.0032 
.0015 

10,869,067 
10.846,777 
10.869,829 

",578,364 
14,321,101 

1  in  55  min.  to  1,194  lbe« 



10,627,046 
10,570,934 
10,550,048 
io,574,77i 
10,617,922 

.0210 
.0193 



10,310,049 

462  MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE    LXXXIII.  (Bar  No.   12).— Continued. 


LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
1,560 
i,  600 

10 

3 
i,  600 
1,640 
i,  680 
1,720 
1,760 
1,  800 
10 

i,  800 
1,840 
i,  880 
1,920 
1,960 

2,000 
IO 

Left  unde 
Resistanc 

3 
2,000 
2,040 
2,080 

2,120 

2,160 

2,2OO 
2,240 

2,28o 

Left  unde 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
2,280 
2,290 
2,300 
2,310 
2,320 
Left  unde 
Resistanc 
Resistanc 
Resistanc 
2,270 
2,280 
2,290 
2,300 
2,310 
2,320 
2,330 
2,340 
2,350,  bean 
Left  unde 
Resistanc 
2,350 
2,360 
2,370 

Inch. 

.4236 

•4395 

.4405 

•  4537 
.4704 
.4332 
.5042 
•  5205 

.5230 
.5333 
.5586 
.5823 
.6076 
.6343 

r  strain. 
*  increased  ii 

.6390 
.6594 
.6856 
.7140 
.7485 

•7777 
.8106 
.8621 
r  strain. 
z  decreased  i 
z  decreased  i 
e  decreased  i 
z  decreased  i 
.8665 
.8685 

.8/22 
.8763 
.8843 

r  strain. 
z  decreased  i 
z  decreased  i 
e  decreased  ii 
.8867 
.8893 
.8919 
.8148 
.8967 
.8990 
.9019 
.9063 

I  sinks.    .9165 
r  strain, 
e  decreased  i 
.9189 
•  923Q 
•  9418 

Inch. 

Pounds. 
2,380 

2,39° 
2,400 
2,410 
•  2,420 
2,430 
2,440 
2,450 
2,460 
2,470 
2,480 
2,490 
2,500 
2.510 
2,520 
2,530 

2,5*0 

2,550 
2,560 

2,57° 
2,580 

2,59° 
2,600 
2,610 
2,620 
2,630 
2,640 
2,650 
2,660 
2,670 
2,680 
2,690 
2,700 
2,710 
2.720 
2,73° 
2,740 
2,750 
2,760 
2,770 
2,780 
2,790 
2,800 
2,810 
2,820 
2,830 
2,840 
2,850 
2,860 
2,870 
2,880 
2,890 
While  p 
sound 
breakir 
Breaking 
Modulus 

Inches. 
•  9529 
.9650 
.9764 
.9888 
.0048 
.0189 
•0333 
.0438 
•  0553 
•0755 
.0865 

•  IOT3 
.1265 
•I34I 
•  1475 
.1647 
.1818 
.1918 
•2073 
.2293 
•2445 
•2585 
.2851 
.3063 
.3288 
.3406 
•3556 
•3747 
•3973 
.4178 
•4447 
.4665 
.4898 
•5057 
•5303 
•5437 
•5^03 
.6106 
.6279 
•6395 
.6581 
.6899 
.7285 
•7599 
•7793 
.8111 

.8553 
.8807 
.8936 
•94^3 
.9881 
Broke  grad 
Jttinff  oh  st 
was  heard 
iff. 
load,/'  =2, 
of  rupture, 

Inch. 

.0407 
.0387 

9,847,245 








•0743 
.0727 

9,354,  J74 



.1340 
.1326 

i  10  min.  to  8 
.1320 

8,955,262 

Ibs. 



5,472,552 





7,651,812 



n  i  min.  to  2,272  Ibs. 
n  3  min.  to  2,268  Ibs. 
n  25  min.  to  2,260  Ibs. 
n  hr.  to  2,256  Ibs. 









::::: 

4,331,697 

n  3  min.  to  2 
n  10  min.  to 
i  66  hr.  13  m. 

312  Ibs. 
2,308  Ibs. 
.02,  260  Ibs. 



ually  in  the  middle, 
rain  a  slight  crackling 
a  few  seconds  before 

880  pounds. 
95,623  (metric,  6,722). 

n  10  min.  to 

2,342  Ibs. 

STRENGTH  OF  COPPER  AL 
TABLE   LXXXIIL— Continued. 

BAR  NO.  52. 

COMPOSITION.— Original  mixture  :  Cu,  60 ;  Sn,  5 ;  Zn,  35. 


LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
3 

10 
20 
40 
80 
120 
1  60 
200 
10 

3 

200 
240 
280 
320 
360 
400 
10 

3 
400 

440 
480 
520 

£ 
10 

600^ 
640 
680 
720 
760 
800 

Inch. 

.0017 
.0036 
.0073 
.0148 
.0237 

.OJ27 
.0408 

.O4ir 
.0497 
.o5d3 
.0656 
.0713 
.0770 

.0777 
.0839 
•0915 
.0993 
.1068 
•H37 

.1148 
.1216 
.1285 

•1353 
.1420 
.1487 

Inch. 

Pounds. 

10 

3 
800 
840 
Beam  sinl 
880 
920 
960 

I  ,OGO 

Inch. 

•1495 

•*55S 
:ing  a  little. 
.1626 
.1698 
•!774 
•1857 

Inch. 
.0058 
.0036 



.0022 
.OOO6 

14,805,645 
14,602,823 
14,389,192 

13,477,5^5 
13,039,862 
13,063,832 

.0063 
.0039 

I4,395,26i 

14,423,245 
14,439,425 
14,421,764 
14,351,218 

3 

1,000 

1,040 
1,  080 

1,120 

160 

200 

!i858 
•1935 
.2032 
.2126 

.2221 

.2324 

.OO26 
.OOO8 

I2,g6o,320 
12,704,4-6 

-2,704,190 

'5,455,93! 
i3,844,27o 

14,324,630 

.0098 
.0072 

13,7^0,839 

3 

200 

240 
280 

320 

360 
1,400 

.2330 
.2426 
•2547 
.2639 
.2722 
.2804 

.0047 
.0026 

I3,975,955 
13,980,442 
13,955,804 
13,973,864 
14,063,440 

.0157 

i  inch  from  t 
402  po  unds. 

R        3/>/ 

13,275,464 

3 
i,402> 
Breaking 

Modulus 
(metric 

Broke  about 
load,  P  =  i 

of  rupture 
,  3,239)- 

tie  middle. 

'.'.     '.'. 

14,626,432 
14,102,841 
14,181,934 
14,263,500 
I4,336,7°9 

1                    2  Id*     ~     4"'U/U 

BAR   NO.   55. 

COMPOSITION.— Original  mixture  :  Cu,  65  ;  Sn,  5  ;  Zn,  30. 


0 

44O 

0856 

14,191,208 

ooT8 

480 

CQ7I 

14,234,223 

20 

£ 

.0037 
.oo8r 
.0168 

• 

14,923,498 

13,633.811 

13,146,888 

520 

560 
600 

oP8 

1058 

1129 

0038 

I4,53°,772 
14,613,175 
14,672,351 

TOO 

.0026 

1-3  084.  s8i 

600 

1I2Q 

640 

14  786  125 

3 

0001 



680 

1265 

1742 



14,840,914 

240 
280 

.0506 

.0581 
0640 

13,094,924 
13.305,285 

760 
800 

1420 
1495 

0064 

J4,776,364 
14,776,762 

*6o 

0781 

14,172,058 

80^ 

1498 

0028 

840 

1-86 

880 

1680 

400 

.0781 

020 

1706 

14,142,413 

464  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS, 
TABLE    LXXXIII.  (Bar  No.  ^.—Continued, 


u.   . 

55 

Ex.     * 

o 

^ 

O 

^  N 

LOAD. 

1 

SET. 

3p 

LOAD. 

i 

SET. 

32 

u 

i§ 

u. 
H 

0  < 

O  J 

Q 

s  « 

Q 

2  w 

Pounds.. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

960 

.  1906 

13,905,628 

1,320 

.3716 

i  ,000 

.2047 

13,487,282 

1,360 

•  4°39 

IO 

.0196 

1,400 

•4433 

8,719,012 

3 

.0177 

10 

.142! 

1,040 

.2185 

1,400 

.4503 

i,  080 

.2382 

1,440 

.4704 

I,I2O 

.2579 

1,480 

.5165 

1,160 

.2789 

1,520 

.5608 

I,2OO 
10 

•3OI4 

•0597 



1,525 

Breakin 

Broke  in  the  middle. 
?  load,  P  —  1,525  pounds 

3 

1,200 

1,240 

•3036 
.3272 

.0576 

10,912,409 

Modulus  of  rupture 

3/y 

1,280 

.358o 

BAR   NO.   64. 

COMPOSITION. -Original  mixture  :  Cu,  75  ;  Sn,  10  ;  Zn,  15. 


3 

10 
20 

£ 

120 

160 

2OO 
10 

3 

200 

240 

280 
320 
360 
400 

10 

3 

400 

44° 
480 
520 
560 
600 

IO 

3 
600 

640 
680 
7|o 
760 
800 

10 

soi- 
ls 

920 

.0019 
.0036 
.006  3 
.0143 
.0223 

•0313 
.0389 

.0390 
.0468 

•  0549 
.0027 
.0702 
.0776 

.0775 
.0843 
.0907 
.0971 
•  I035 
.1107 

.1115 
.1:79 
.1251 
.1323 
•^QS 
.1472 

:i482 

•  T557 
.1647 
.1738 

960 
1,000 

10 

3 
1,000 
1,040 

,080 

,120 

,160 

,200 
10 

3 

,200 

,240 
,280 
,320 
,360 

,400 

10 

3 

,400 

,440 
,480 
,520 
,560 

,600 

IO 

3 

.600 

,640 

,680 
,720 
750 
Breaking 
Modulus  o 

t 

.1847 
.1979 

.2001 
.2113 
.2258 

•24|8 
.2661 
.2858 

.2927 

•3077 
.3286 
.3536 
.3816 
.4111 

!4is6 
•4413 

•  4795 
.5234 
0598 
•5947 

.6090 
•6399 
•6755 
•7339 
Broke  near  t 
oad,  /*=  1,7 
f  rupture, 

'-;£=* 

.0224 

.0195 

.0637 
.0607 

•  1473 
•M43 

14,148,277 
13,754,775 

11,429,344 

.0024 

.0032 

I5,I22,6l3 
l6,OI2,I77 
15,228,364 
14,264,121 

13,9*4,7?7 
13,995,219 

.OO26 
.OOO3 

.0049 
.0021 

^.gs^aa1 

I3<8^3,543 
13,892,545 
1  3,959,33' 
14,031,290 

14,207,721 
14,405,661 
M,577,5" 
14,728,108 
14,752,853 

9,270,002 

•••'• 

.2840 
.2798 

.Oo8l 
.0057 

14,776,293 
14,796,224 
14,813,990 
14,829,914 
14,793,825 

tie  middle. 
50  pounds. 

J,345  (metric,  4,102). 

14,685,542 
14,544,151  ! 
14.409,115  j 

STRENGTH  OF  COPPER  ALLOYS. 
TABLE  LXXXIIL— Continued. 

BAR  NO.   68. 

COMPOSITION. — Original  mixture  :  Cu,  80 ;  Sn,  10 ;  Zn,  10. 


465 


LOAD. 

DEFLECTION. 

SET. 

MODULI'S  OP 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

9,372,595 

Pounds. 
3 

IO 
20 

g 

120 
1  60 
200 
10 

3 

200 

240 
280 
320 

400 
520 

10 

60? 

640 
680 
720 

760 

800 

10 

•s 

960 

1,000 
10 

3 

1,000 

1,044 

1,  080 

1,120 

1,  160 

Inch. 

.0019 
.0038 
.0.72 
.0132 
.0210 
.0291 
•0374 

•0374 
.0456 
•0536 
.0617 

.0853 
.0921 
.0991 
.1063 
.1120 

•"37 
.1208 
.1286 
•1365 

.1528 
.1625 
.1725 
.1839 

•«9SS 

.2126 

!2i66 
.2323 
•  2527 

Inch. 

0025 
0006 

i  Pounds. 

1,200 
10 

3 

1,200 

1,240 
1,280 

1,320 
1,360 

MOO 

10 

3 
1,400 
1,440 
1,480 
1,520 
1,560 
i,  600 
10 
,  3 

I,COO 

1,640 
1,  680 

1,720 
1,760 

1,800 

10 

i,8co 
1,840 
i,  880 
1,920 
1,960 

2,000 
2,040 

2,c6o 
Rollers  fle 
iron  sup 
with  a  t< 
Coefficient 
Breaking  1 
Modulus  o 

R 

Inches. 

•3325 

•3419 
.3627 

.4037 
.4400 

•4934 
•5647 

•5720 
.6010 
.6449 

•7M3 
.7921 
-8645 

".8808 
.9409 
.0216 
•i  '57 
.2321 
•3417 

^ 
.5879 
-7029 
.8499 
.0079 
.2849 
•4479 
w  apart.    Cc 
aorts.  Theb. 
)tal  deflectio 
of  elasticity 
oad,  P  =  2,o< 
f  rupture, 

=  —     ,  =  67 

Inch. 

.1171 
•  «53 

14,427,725 
15,739,237 
'4,839,942 
14,278,983 
13,887,648 



.2951 
•2934 

6,438,437 



0067 
0053 

13,668,369 
13,566,365 
13,468,990 

13,379,554 
13,266,871 
'3,395,96' 
'3.534,458 
13,626,9^7 
13,681,226 
13,911,448 

'5468 
•  5432 

4806,460 

0150 
0130 

'3,759,793 
13,732,139 
13,608,407 
I3,668,368 
13,614,630 

^9589 
•  9546 

3,484,072 

2,586,772 

mtinued  tests  on  cast- 
ir  broke  at  2,320  pounds 
[i  of  2.797". 
,  2,154,009. 
to  pounds. 

117  (metric,  4,718). 

.0417 
.0405 

12,215,380 

30 


466  MATERIALS  OF  ENGINEERING— NON-FERROUS  ME  TALS. 
TABLE    LXXXIII.— Continued. 

BAR   NO.    71. 

COMPOSITION.— Original  mixture  :  Cu,  85  ;  Sn,  10  ;  Zn,  5. 


LOAD. 

g 

g 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
3 

10 

20 
40 
90 
1  20 
160 
200 

10 

3 

200 

240 
280 
320 
360 
400 
10 

3 
400 
440 
480 
520 
560 
600 

10 

600 
640 
680 
720 
760 
800 

10 

Sol 

840 

880 

920 
960 
Left  unde 
Resistanc< 
Resistance 
Resistance 
Resistance 
Resistance 
Resistancr 
Resistance 
Resistance 
Resistanc 
Resistanc 
Resistanc 
Resistance 
920 
940 
945 
950 
955 

Inch. 

.0013 
.0031 
.0064 
.0131 
.0201 
.0275 
•°3S5 

.0364 
.0420 
.0508 
.0589 
.0670 
.0752 

•°759 
.0842 
.0919 
.0998 
•1073 
•  «35 

.1141 
.1138 
.1270 
•!347 
.1425 
.1501 

.1506 
.1598 
.1691 
.1787 
.1894 
r  strain. 
:  decreased  i 
;  decreased  i 
:  decreased  i 
:  decreased  i 
:  decreased  i 
:  decreased  i 
:  decreased  i 
;  decreased  i 
:  decreased  i 
;  decreased  i 
i  decreased  i 
;  decreased  i 
.1896 
.1914 
.1920 
•  1943 
.1951 

Inch. 

Pounds. 
960 

965 
970 

975 

985 
990 
1,000 

10 

3 

1,000 

1,040 
1,  080 

I,I2O 

1,160 
Left  unde 
Resistance 
Resistance 
Resistance 
Resistanc 
Resistance 
Resistance 
Resistance 
Resistanc 
Resistance 
Resistance 
i,  066 

I,  TOO 
I,  IIO 
1,120 
1,130 
1,135 
1,140 
I,t45 
1,150 

M55 

1,160 
x,'65 
1,170 
i,i75 
1,180 

1,200 
10 

3 

1,200 
1,240 
1,280 
''320 
1,360 
1,400 
10 

3 
1,400 
1,440 
1,480 
1,520 
1,560 

Inch, 

.1958 
.1969 
.1983 
.1994 
.2005 
.2017 

!2o66 

.2078 
.2166 
.2306 

•  2537 
.2832 
r  strain. 
;  decreased  i 
j  decreased  i 
;  decreased  i 
i  decreased  i 
:  decreased  i 
;  decreased  i 
;  decreased  i 
;  decreased  i 
;  decreased  i 
;  decreased  ir 
•  2833 
.2897 
.2914 
.2937 
.2958 
.2970 
.2986 
.3005 
.3023 

•  3°45 
.3076 
.3110 
.3Hi 
•  3^75 
.3221 

.3304 

.3305 
.35X1 

.3691 
.4204 
.4704 
.5296 

.5500 
.6052 
•6534 
•735<5 
.8214 

Inch. 

.0024 
.0015 

.0042 
.0026 

15,737,2i7 
15.245,428 
14,896,295 
14,562,759 
14,192,102 
13i742,357 



•°397 

.0382 

11,806,720 

13,742,357 

I3,444,786 
13,252,393 
13,106,5  :6 
12,974,833 



n  2  min.  to  1,118  Ibs. 
i  3  min.  to  1,112  Ibs. 
i  4  min.  to  1,110  Ibs. 
i  7  min.  to  1,104  Ibs. 
i  12  min.  to  1,100  Ibs. 
i  27  mm.  to  1,093  lbs- 
n  42  min.  to  1,090  lbs. 
i  i  hr.  i2m.  to  i,  087  lbs. 
i  2  hr.  i2m.  to  1,082  lbs. 
16  hr.  i2m.  to  1,066  lbs. 

!<x>68 
.0051 

12,746,771   1 
12,740,466 
12,703,614 
10,730,571 
12,906,151 

•  0134 
.0116 

13,031,152 
13,060,650 
13,038,405 
13,009,131 
13,000,763 



•   ••• 

'.'.'.'.. 





i  i  min.  to  94 
i  2  min.  to  9< 
i  3  min.  to  9; 
i  4  min.  to  9^ 
i  9  min.  to  91 
i  14  min.  to  $ 
i  29  min.  to  c 
ti  44  min.  to  g 
ti  i  hr.  i4mir 
n  i  hr.  44  mil 
n  2  hr.  44  mil 
n  2  hr.  74  mil 

4lbs. 
olbs. 
8lbs. 
7  lbs. 
albs. 
30  %  Ibs. 
26  Ibs. 
25  Ibs. 
i.  to  9^3  Ibs. 
i.  to  922  Ibs. 
i.  to  9  20  Ibs. 
i.  to  920  Ibs. 

!ii66 
.1141 

8,859,329 

.2794 
.2764 

6,448,116 





STRENGTH  OF  COPPER  ALLOYS. 
TABLE  LXXXIII.  (Bar  No.  71).— Continued. 


467 


LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

Inch. 

it 

Pounds. 

1,  600 

10 

1,  600 

1,640 
1,  680 

''720 

1,760 

1,800 
1,840 
1,880 

Inches. 
.0206 

'.9486 

1.0198 

1.1191 

1.2726 
1-3791 
1.5061 
1.6896 
1.8556 

Inch. 

Pounds. 

1,920 

1,960 

2,000 

The  bea 
crease 
Breaking 
Modulus 

< 

Inches. 

2.0401 
2.3676 
2.5621 
m  could  not 
of  load, 
load,  P  =  2, 
of  rupture, 

.6169 

.6132 

be  raised  with  an  in- 
ooo  pounds. 

62,470  (4,392  metric). 

BAR  NO.  72. 

COMPOSITION. — Original  mixture  :  Cu,  90;  Sn,  5 ;  Zn,  5. 


3 

10 

20 

C 

120 

160 

200 
10 

3 

200 

X 

IS 

400 
10 

3 
400 

% 

520 

£ 

10 

600 
640 
Left  unde 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
591 
£20 
625 

.0018 
.0036 

.0145 

.0221 
.0297 
•0374 

:0376 

.0461 
•°535 
.0608 
.0681 
•0754 

•0757 
.0827 
.0007 
.0992 
.1092 

.  I2O2 

.1246 
.1342 

r  strain. 
2  decreased  i 
2  decreased  i 
2  decreased  i 
2  decreased  i 
2  decreased  i 
2  decreased  i 
2  decreased  i 
2  decreased  i 
2  decreased  i 
2  decreased  i 
2  decreased  i 
•  1342 
•1387 
.1392 

630 
635 
640 

<45 
650 

IS 
680 

7f° 
760 
800 

10 

ao! 

840 
Left  und 
Resistan 
Resistan* 
Resistan* 
'Resistan 
Resistanc 
Resistan< 
Resistan 
Resistanc 
Resistan* 
Resistan* 
Resistan* 
Resistanc 
Resistam 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
Resistanc 
752 
780 
800 
820 
825 
830 

I35 
840 

•'397 
.1406 
-14'S 
.1426 
.1441 
.1456 
•1473 
•1525 
•I7°i 
.1969 
.2287 

.2451 
.2814 
er  strain. 
:e  decreased 
:e  decreased 
:e  decreased 
:e  decreased 
:e  decreased 
:e  decreased 
:e  decreased 
:e  decreased 
:e  decreased 
:e  decreased 
:e  decreased 
:e  decreased  i 
•e  decreased 
e  decreased 
•e  decreased 
e  decreased 
e  decreased  i 
e  decreased 
e  decreased 
.2814 
.2865 
.2900 
•  2951 

33 

•  3050 
•3094 

-0035 
.0019 

14,309,323 
14,862,866 
14,145,348 

13,921,359 
13,811,961 
13,710,398 

•0997 
.0979 

8,968,410 

.0071 
.0049 

13,347,532 
13,418,250 
i3,493,9!9 
13,553,364 
13,601,300 

in    i  m.  to  800  Ibs. 
in    2  m.  to  795  Ibs. 
in    3  m.  to  792  Ibs. 
in    4  m.  to  790  Ibs. 
in    5  m.  to  789  Ibs. 
in    6  m.  to  788  Ibs. 
in  13  m.  to  782  Ibs. 
in  21  m.  to  779  Ibs 
in  31  m.  to  777  Ibs. 
in  46  m.  to  774  Ibs. 
in    i  hr.  i  m.  to  772  Ibs. 
n  ihr.  i6m.t077iilbs. 
in  i  hr.  46  m.  to  770  Ibs. 
in  3  hr.  i  m.  to  766  Ibs. 
in  4  hr.  i  m.  to  764  Ibs. 
in  5  hr.  31  m.  to  763  Ibs. 
n  21  hr.  15  m.  to  752*105. 
in  23  hr.  45  m.  to  752  Ibs. 
n  24  hr.  36  m.  to  752  IDS. 

.0246 
•0233 

13,640,770 
13,568.306 
13,439,504 
13,180,961 
12,797,923 

n    i  m.  to  628  Ibs. 
n    2  m.  to  626  Ibs. 
n    3  m.  to  624  Ibs. 
n    4  m.  to  623  Ibs. 
n    5  m.  to  622  Ibs. 
n   6  m.  to  621  Ibs. 
n  ii  m.  to  618  Ibs. 
n  i6m.  to  617  Ibs. 
n  19  hrs.  51  m.  to  596  Ibs. 
n  40  hrs.  36m.  to  591  Ibs. 
n  42  hrs.  1  1  m.  10591  Ibs. 

468    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE  LXXXIII.   (Bar  No.  72).— Continued. 


o 

»t 

0 

sg 

LOAD. 

w 

SET. 

j§  D 

^  H 

LOAD. 

1 

SET. 

>->   H 

3 

It, 

D< 

-1 

Q  < 

w 

O  >-> 

0 

X 

Q 

Pounds. 

Inches. 

Inch. 

Pounds. 

Inches. 

Inch. 

845 

.3175 

I,I2O 

1.3085 

850 

.3237 

860 

i  802  s 

6 

880 

.3510 

1,240 

,     9,  9 

920 
960 

.4320 

.5587 

1,280 
The  bean_ 

2.6325 
i   could  not 

be  raised  w 

ith  an   in 

1,000 

.7191 

3,565,351 

crease  of  weight. 

10 

3 

.5485 
•  5455 

Breaking  load,  P  —  1,280  pounds. 
Modulus  of  rupture, 

1,000 

.7567 

1,040 

.8634 



R  —  -—  -  =  41,334  (2,906  metric). 

1,  080 

I.IOOI 

BAR    NO.    73. 

COMPOSITION. — Original  mixture:  Cu,  55  ;  Sn,  5  ;  Zn,  44.5. 


3 

10 
20 

£ 

120 

160 

200 
IO 

3 

200 
240 
280 
320 
360 
400 
10 

3 
400 

$ 

IF 

600 

10 

60! 

640 

680 
720 
760 

800 

10 

800 
840 
880 
920 
960 

1,000 
10 

.  3 
1,000 
1,040 
1,  080 

1,120 
1,100 
I,2OO 

.0021 
.0051 
.0122 
.0217 
.0321 
.0417 
.0519 

.0520 
.0631 

•°734 
.0813 
.0899 
.1001 

.0997 

.IIO2 
.1199 
.1300 
.1402 
.1516 

.1518 

•  J623 

:3£ 

.2024 
.2164 

.2167 
.2296 
•  2443 

.2585 
•2758 
.2923 

!2948 

.3146 
.3338 
•  3571 
•  3*5* 
.4271 

10 

3 

,200 
,240 
,280 
,320 
,360 
1,400 
IO 

Left  und 
Resistam 
Resistam 

IO 

3 
1,400 
,440 
,480 
,520 
,560 
,600 
,640 
,680 
,720 
,760 
,8co 

10 

3 

,800 
,840 
,880 
,920 
,960 
ooo 

10 

3 
2,000 

2,000 
2,040 
2,080 
2,100 

Breaking 
Modulus 

j 

.4284 

•4575 
•4973 
•  539° 
.5876 
.6419 

er  strain. 
:e  increased 
:e  increased 
.2970" 
•  2933 
.6508 
.7197 
•7853 
•  8571 
•9485 
.0361 
•1295 
.2316 
•3347 
•4535 
•5744 

!5866 

•7459 
.8619 
.0244 
.2087 
.3178 

.3513 
•7738 
3.0498 
3.0498 
Beam  coul 
this  pres 
load,  P  =  2, 
of  rupture, 

?  _  3/v  _ 

~27^~   ' 

.1286 
.1265 

.0024 
.0024 

.002  3 
.0008 

11,125,506 
9,301,654 
10,459,002 
10,605,623 
10,885,388 
io,932,579 



[2986 
.2965 

n  20  m.  to  >-j 
n  15  hrs.  45  "ir 

6,187,577 

10,790,506 

10,822,358 
11,166,563 
11,360,639 
11,336,420 

Ibs. 
.  to  10  Ibs. 



::::.' 

4,381,050 

.0046 
.0018 

.0140 
.0119 

.0440 
.0417 

11,327,423 
11,357,480 

11,348,016 

11,331,828 

11,22^,276 

11,187,203 
ri,o;5,376 
10,859,347 
10,652,784 
10,015,963 

10,379,284 
ro,2i9,254 
10,996,882 
9,874,995 
9i705,798 

1.1384 
1.1358 

1.9144 
1.9096 

3,243,526 

2,448,014 

d  not  be  raised  aftef 
sure  was  attained, 
loo  pounds. 

2,308  (metric,  5,083). 

9,378,526 
9,179,045 
8,897,912 



7,970,978 

STRENGTH  OF  COPPER  ALLOYS. 
TABLE  LXXXIII.— 


469 


BAR    NO.    74. 

COMPOSITION.—  Original  mixture  :  Cu,  67.5  ;  Sn,  5  ;  Zn,  27.5. 


LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

i 

b 

• 
Q 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
3 

JO 
20 

4° 
80 

120 
1  60 
200 
10 

3 

203 
240 
280 
320 
360 
*       400 
10 

3 
400 
440 
480 
520 

& 

600 

10 

<£ 

640 
680 
720 
760 
800 

10 

Sol 
840 
880 

Inch. 

.0016 
.0033 
.0070 
.0140 
.0218 
.0294 
•0393 

.0396 
.0482 
.0562 
.0642 
.0727 
.0809 

!o8o7 
.0886 
.0963 

•1037 
.1107 
.1180 

•  "77 
•  1255 
•  iS'S 
•'379 
.1442 
.1508 

.I5H 

::& 

Inch. 

Pounds. 
920 
960 

1,000 
10 

3 

1,000 

1,040 
1,  080 

1,120 

1,160 

1,200 

10 
3 

1,200 

1,240 
1,280 

1,320 

1,360 
1,400 

10 

3 
1,400 

1,440 
1,480 
1,520 

1,560 
1,  600 

10 

1,600 

1,640 
1.  660 

Breaking 
Modulus 

1 

Inch. 
.1721 
.1801 
.1888 

!is98 
.1980 
.2083 

.2211 

•23|3 
.2469 

.2498 
.2632 
.2791 
.3013 

••3I^ 
.3360 

^3396 
•3521 
.3727 
.4013 
•4301 
.4620 

.4621 
.4874 
Broke, 
load,  /»=!, 
of  rupture, 

'-35- 

Inch. 

.0083 
.0068 

14,871,767 
H,794,934 
14,701,230 

.0025 
.0009 

16,821,775 
17,390,724 
15,208,723 
15,278,489 
15,105,267 
14,125,146 



14,578,869 
14,390,973 



.0190 
•0175 

13,490,121 

.oo?8 
.0013 

13,820,378 
13,828,573 
13,834,729 
13,712,725 
13,723,572 



12,i59.9I3 

.0039 
.0024 

13,783,981 
13,834,726 
13,918,109 
14,040,945 
M,"3,l85 

.0521 
.0503 





10,513,107 

.0044 

.0032 

14,154,417 
14,352,805 

ES® 

14,724,630 

.1167 
.1151 



9,610,361 

660  pounds. 
,976  (metric,  3,935). 

-j 

'....'. 

14,784,385  j 
14,857,187 

BAR  NO.  76. 

COMPOSITION.—  Original  mixture  :  Cu,  80  ;  Sn,  12.5  ;  Zn,  7.5. 

3 

10 
20 

£ 

120 
1  60 
200 
IO 

3 

200 
240 
280 
320 

.OO2I 
.0053 
.0109 
.0193 
.0271 
.0361 
.0463 

!o468 
.0^46 
.0614 
.0682 

^ 

400 

10 

3 
400 
440 
480 
520 

£ 

600 

10 

Left  und 

Resistanc 

.0750 
.0826 

.'0824 
.0897 
.0964 
.1031 
.nor 
.1166 

:r  strain, 
e  increased  i 

0046 

OO22 

12,714,988 
12,827,876 

0040 
0016 

9,996,061 
9,720,941 
10,980,131 
11,729,695 
11,740,527 
"i442,576 

0057 
0035 

n  i  hour  to  6 

I2,993,767 
13,189,824 
i306o,397 
i3»473,348 
13,630,993 

.... 

11,643,764 
12,079,930 
12,429,120 

pounds. 

4/0  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE  LXXXIII.  (Bar  No.  ^.—Continued. 


LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 

600 
640 
680 
720 
760 
800 

10 

3 
800 
840 
880 
920 
960 

1,000 
10 

3 

1,000 

,040 
,080 

,120 
,100 
,200 
10 

3 

,200 
,240 
,280 
,3|0 
,360 
,400 
10 

Inch. 

.1167 
.1232 
.1301 
.1366 
.1440 
.1506 

.1506 
•1587 
•1675 

•1954 

.1976 
.2064 

.2173 
.2299 

•2434 
•2594 

!2646 
.2766 
.2926 
.3126 
•3313 
•3529 

Inch. 
.0031 

.'0081 
.0064 

Pounds. 
3 
,403 
,440 
,480 

,520 

,560 
,600 

IO 

,^ 

,640 

,680 
,720 

,760 

,800 

10 

3 
,800 
,840 
,880 

,Q20 
,960 
,OOO 
10 

Broke  wl 
had  rez 
Breaking 
Modulus 

. 

Inch. 

!3026 

•3791 
.40^6 

.4364 
.4656 
.5081 

.5^3 
•5364 
.5706 
.5986 

•^559 
.6990 

.7148 
•7579 
.7965 
.8485 
.9090 
.9652 

lile  putting 
iched  1,950  p 
load,  P=2, 
of  rupture, 

-fi- 

Inch. 
.0964 

13,760,813 

I3.845>426 

13,962,296 
13,980,603 

14,071,480 

1 

.2011 
.1983 

8,209,046 

.0182 
.0156 

14,020,942 

13,950,222 
13,791,965 

i3>671>°35 
I3i556,58i 



.3462 
•  3425 

6,821,346 

13,347,452 

^5518 
•5473 
strain  on  anc 
Dunds. 
ooo  pounds. 

5,073  (metric 

5,508,330 

.0447 
.0428 

12,254,229 

1  before  it 

4,645). 

.0991 

10,508,678 

BAR  NO.   77. 

COMPOSITION. — Original  mixture:  Cu,  82.5  ;  Sn,  15  ;  Zn,  25. 


3 

10 
20 
40 
80 

120 

160 


3 

200 
240 
280 
320 
36o 
400 
10 

3 
400 


.0012 
.0031 
.0071 
.0154 
•0235 
.0307 
.0421 


.0422 
.0498 
•0575 
.0655 
.0732 
.0800 


.0802 
.0874 
.0950 
.1017 
.1090 


.OO2I 
.0006 


.0025 
.OOI2 


17,107,474 
14,938,924 
13,774-851 

I3,54°,381 
13,819,719 
12,596,953 


12,779,076 
12,912,424 
12,954,669 

13,040,943 
13,258,292 


13,349,313 
13^396,852 
13,558,134 
13,623,198 


6oo 

10 

3 

603 

640 
680 
720 
760 
800 

10 

Left  under  strain. 
Resistance  increased  in 
.0046 


"55 


.1161 
.1217 

.1286 
.1361 

•  1437 
.1506 


.0027 
.0014 


i3,774,45i 


10 
So? 

840 

880 

920 

960 

1,000 

10 

3 


,1463 
.  1562 
,1627 
.1691 

•  1775 

•  1857 


13,944,630 
14,021,209 
14,027,877 
14,024,081 
14,085,034 
.0046 

27  hrs.  50  m  to  14  Ibs. 


.0043 
.0027 


.0125 
.0105 


14,259,881 
14,342,099 
I4,425,528 
14,341,363 
14.279,259 


STRENGTH  OF  COPPER  ALLOYS. 
TABLE  LXXXIII.(Bar  No.  77).— Continued. 


471 


LOAD. 

Q 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

Q 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
1,000 
1,040 
i,  080 

1,120 

1,160 

1,200 
10 

3 

1,200 
1,240 
1,280 

X'3£ 
1,360 

1,400 
10 

3 
1,400 
1,440 
1,480 
1,520 
1,560 
1,600 

10 

1,600 

Inch. 
.1862 
.1940 
.2049 
.2165 
.2310 
•2447 

'2473 
.2015 
.2791 
.2992 
•3^74 
•339° 

•  3430 
•3599 
.3860 
.4150 

3? 

.4929 

Inch. 

Pounds. 
1,640 
1,680 

''720 

1,760 
1,800 
10 

,,80! 

1,840 

1,880 
1,920 
1,960 

2,000 
10 

3 

2,000 
2,040 
2,o8o 
2,000 

Breaking 
Modulus 

. 

Inches. 
•5167 

ioSo? 

.6950 
•7356 
.7842 
.8311 
.8924 
.9558 

.9762 
1.0197 
1-0895 
Broke 
load,  P=2, 
of  rupture, 

*=£.=• 

Inch. 

...  . 

14,215,075 

.0311 

.0275 

13,003,632 

:3i8i 

•  3!56 

7,011,877 

— 



•5305 
•5247 

5,548,564 

.0822 
.0800 

10,823,095 

090  pounds. 
9,045  (metric,  4,854)- 

.1730 
.1705 

8,607,535 

BAR   NO.    78 

COMPOSITION.— Original  mixture  :  Cu,  60  ;  Sn,  2.5  ;  Zn,  37.5. 


3 

10 
20 

£ 

120 
160 
200 
10 

3 

200 
240 
280 

3*° 

360 
400 

10 

3 
400 
440 
480 
520 

& 

10 

60^ 
640 

.0014 
.0079 
.0119 
.0197 
.0284 
•0357 
.0431 

.0446 
•°5i3 

.0000 

.0756 

.0839 

!o84o 
.0917 
.0996 

:S3 

•  1235 

.1239 
.1319 

680 
720 
760 
800 
IO 

800 
840 
880 
920 
960 
1,000 

10 

3 

1,000 

1,040 

1,  080 

1,120 
1,  100 
1,200 
10 

3 

1,200 

1,240 
1,280 
Left  und 
Resistanc 
Resistan 

.1307 
.1489 
.1581 
.1676 

:i683 
•  1785 
.1887 
.2010 
.2137 
.2256 

.2244 
.2426 
•  2595 
.2791 
.2998 
•  3244 

•3245 

& 

?r  strain. 
:e  decreased 
:e  decreased 

!oo83 
.0070 

13,698,602 
13,608,229 
i3,528,37i 

1  3,  432  ,2  10 

.0019 

.0001 

.0013 
.0002 

7,124,701. 
9,459,685 
11,428,458 
11,891,227 
I2,6l2,9l8 
13,059,  '98 

13,243,564 
13,124,254 

I3,l66,II2 
13,133,199 
13,185,394 
13,401,225 
I3»4I7,197 

.0215 

.0201 

12,474,544 



.0032 
.0012 

13,503,526 
13,562,685 
13,562,685 
13,609,517 
13,672,506 

!o566 
•  0546 

10,410,323 

13,655,229 

in  2  min.  to  1,265  I08- 
in  4  min.  to  1,260  Ibs. 

47  2  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE    LXXXITI.  (Bar  No.  78).— Continued. 


LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

§ 

h. 
Id 
Q 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
Resislanc 
Resistanc 
Resistanc 
Resistanc 
,260 
,270 
,280 
,2go 
,300 
,320 
,360 
,400 
10 

3 
,400 
,440 
,480 
,520 
,560 
,600 
10 

i,  600 

Inch. 
z  decreased  i 
2  decreased  i 
e  decreased  i 
:  decreased  i 
•  3699 
•37^8 
.374i 
.3762 
.3788 
.3852 
•4311 
.4760 

•  4775 
•  501  7 
•  5430 
•  596S 
.6476 
.7044 

.7064, 

Inch. 
n    7  min.  to 
n  22  min.  to 
n  4  h.  52m.  t 
i  12  h.  32  m. 

1,257}  Ibs. 
1,253*  Ibs. 
3  1,245}  Ibs. 
to  1,244  Ibs. 

Pounds. 
1,640 

1,  680 

1,720 

1,760 

1,800 

10 

3 
i,  800 
1,840 
i,  880 
1,920 
1,960 
2,000 

10 

3 
2,000 
2,030 
Breaking 
Modulus 

R 

Inches. 
•7345 
•7979 
.8654 
.9268 
1.0156 

.0181 
.0456 
•'L5I3 
.2366 
.3206 
.4426 

1-4574 
Broke  in  th 
load,  P  =  2 
of  rupture, 

3/Y       « 

-2^3  = 

Inch. 

* 

•5333 
.5306 

4,987  853 







!882i 
.8800 

e  middle. 
030  pounds. 

9,508  (metric 

3,901,644 

.1381 
.1360 

8,277,226 





,  4,886). 

.2942 
.2921 

6,392,409 

BAR   NO.    80. 

COMPOSITION.— Original  mixture :  Cu,  77.5  ;  Sn,  10;  Zn,  12.5. 


3 

10 
20 

40 
80 

120 

160 

200 
IO 

3 

200 
240 
280 
320 
360 
400 
IO 

3 
400 
440 
480 
520 
560 
600 

10 

3 
600 
640 
680 
Left  unde 
Resistanc 

.0014 
.0083 

.0111 

.0208 
.0290 
.0368 
.0448 

.0449 
.0523 
•°585 
.0661 
.0740 
.0814 

.0810 
.0884 
•°955 
.1025 
.1095 
.1165 

;»65 
•1235 
.1304 

r  strain, 
e  decreased  i 

680 
720 
760 
800 

10 

sol 

840 
880 
920 
960 

1,000 
10 

3 

,000 

,040 

,080 

,I2O 

,160 

,200 
IO 

3 

,200 
,240 
,280 
,320 
,360 
,400 
IO 

3 

1.400 

.1315 
.1364 

•I445 
•1515 

''I24 
.1601 

.1690 
.1809 

•'959 
.2099 

.2130 
.2251 
.2419 
.2613 
.2824 
•  3023 

'3086 
•3249 
•  -3445 
•3765 
.4039 
•4475 

.4  50  5 

.0104 
.0085 

13,87^289 
13,821,159 
13,876,377 

.0019 
.0005 

6,332,  141 
9,469,689 
10,107,072 
10,873,815 
"»425i387 
",731,423 

.0297 
.0279 

!3,787,536 
13,683,421 
13,364,351 

12,519,481 

.0024 

.0010 

12,058,914 
12,577,687 
12,721,759 
12,784,079 
12,913,211 





.0045 
.0029 

n  43  min.  to 

13,079,741 
13,207,981 
*3,33M72 
I3,439ii73 
I3,533.934 

13,617,950 
13,703,452 

672  pounds. 

.0770 
•  0752 

10,431,381 



.1776 
•  1747 

8,221,172 

STRENGTH  OF  COPPER  ALLOYS. 
TABLE  LXXXIII.  (Bar  No.  80).— Continued. 


473 


LOAD. 

j 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 

1,440 
1,480 
1,520 

1,560 
1,600 

10 

3 
i,  600 
1,640 
1,680 

1,760 
1,800 

Inch. 

.4880 
•  5215 
•5710 
.6148 
.6675 

!676o 
.7096 
•7573 
•  8255 
.8785 
.9628 

Inch. 

Pounds. 

10 

,,*J 

1,840 
1,  880 

1,920 
1,960 
Breaking 
Modulus 

Inches. 

•  9777 
1.0177 
1.0903 
i  .  1930 
Broke  just 
load,  P  =  i 
of  rupture, 

Inch. 

•  5756 
•  5718 

•3435 
•3410 

6,293,140 

after  beam  rose. 
,960  pounds. 

,849  (metric,  4,489). 



4,912,868 

BAR  NO.   87. 

COM°OSIT~ON. — Original  mixture  :  Cu,  77.5  ;  Sn,  12.5;  Zn,  10. 


3 

10 
20 

c 

120 

1  60 
200 
10 

3 

200 
240 
280 
3fO 
360 
400 
10 

3 
400 
440 
480 
520 
56o 
600 

10 

'600 
640 
680 
720 
760 
800 

10 

hi 

840 
880 
920 
960 

1  ,000 

10 

.0018 

.0063 

.0108 
.0185 
.0263 
•0336 

•Q4I5 

.0427 
.0520 
.0603 
.0675 
•0743 
.0816 

.0817 
.0887 
.0958 
.1025 
.1089 
•  «53 

.1161 
.1219 
.1284 
.1348 
.1413 
.1485 

•T493 
•1557 
.1630 
.1707 
•1794 
.1897 

3 
1,000 

1,040 
1,  080 

1,120 

1,160 

I,2OO 
10 

3 

1,200 

1,240 
1,280 
1,320 

1,360 
1,400 

10 

3 

1,400 
,440 

,480 
,520 
,560 

,600 

IO 

1,  600 
1,640 
1,680 
1,720 
1,760 
1,800 

IO 

1,800 
1,825 
Breaking 
Modulus 

j 

.  1912 
.2004 
.2113 
.2225 

•  2377 
.2570 

.2592 
.2705 
.2845 
.3029 
.3240 
•3493 

•3553 
.3690 
•39°5 
•4*34 
•4597 
•4950 

5°43 
•  5225 
.5513 
.6008 
.6490 
.6885 

Bro'lce50 
load,  P=  i, 
of  rupture, 

'=£=« 

.0106 

.0021 

.OOO6 

•°035 
.00l8 

.0043 
.OO2I 

8,550,829 
9,975,965 
11,647,614 
12,289,782 
12,826,242 
12,980,775 







,0380 
.0348 

12,576,762 

12,431,587 

I21507.172 
12,769,235 
12,050,657 
13,203,483 



10,795,632 

.0892 

13,361,271 
13,495,668 
13,664,637 
'3*850,936 
14,016,565 

!i865 
.1830 

8,706,298 

.0055 
.0038 

14,141,485 
14,264.731 
14,386,704 
14,486,388 
14,510,495 

!3288 
.3245 

7,041,858 

825  pounds. 
1,705  (metric,  4,538). 

::::: 

14,531.465 
I4,54Ii654 
14,516,869 
M.413'435 

.0119 



474  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE  LXXXIIL— Continued 

BAR  NO.  88. 

COMPOSITION.—  Original  mixture  :  Cu,  82.5  ;  Sn,  12.5  ;  Zn,  5. 


LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Pounds. 
3 

10 

20 

40 
80 

1  20 
160 

200 
10 

3 
200 

240 
280 
320 
360 
400 

10 

3 
400 
440 
480 
520 
560 
600 

10 

^ 

640 
680 
720 
760 
800 

10 

*2 

i£ 

920 
960 

1,000 
10 

3 
1,000 
1,040 
1,  080 

I,I2O 

1,160 

1,200 

Inch. 
.0020 

.0047 

.0090 

.0075 

.0254 
.0338 
.0410 

.0411 

.0509 
.0590 

.0666 

•0739 
.0810 

iosie 
.0888 
.0958 

.102  1 

.1097 
.1171 

.1169 

.1231 
.1310 
•  1373 
.1451 

.1528 

•»534 

.1608 

.1783 
.1880 
.1983 

.'^988 
.2090 
.2206 
•  2341 
.2502 
.2675 

Inch. 

Pounds. 

10 

3 
,200 
,240 
,280 
'320 
,36o 
,400 

10 

3 
,400 
,440 
,480 
,520 
,56o 
,600 
10 

,60! 

,640 
,680 
'720 
,760 
,800 

10 

Left  und 
Resistant 

10 

i,  800 
1,840 
i,  880 
1,920 
1,960 
2,000 

10 

3 
2,000 
2,040 
2,080 

2,120 

Broke  ju 
Breaking 
Modulus 

Inch. 
.2726 

.2864 

.3065 

•3258 
.3487 

•373° 

.3825 
.4017 
.4326 

•  4733 
.5062 
•  5520 

.5649 
•5875 
.6242 
.6828 
.7412 
.8048 

er  strain. 
:e  increased 

isioS 
.8490 
.9086 
.9788 
.0530 
.1326 

•  1576 
•  2173 
.2980 
.6100 
st  after  beair 
rload,JP^2) 
of  rupture, 

-&- 

Inch. 
.0520 

.0494 

.0023 
.0003 

.0038 
.0017 

.0050 
.0039 

11,327,661 
11,831,112 
12,169,145 
12,576,378 
12,601,287 
12,985,365 

I2i55I?67i 



."53 

.1124 

9,991,423 

12,790,394 
12,967,797 
13,145,680 

13,190,091 
13,377,788 
*3,557,69! 
13,589,062  ; 
13,639,627  | 

•2431 
.2399 

7,715,943 

^4380 
•  4328 

in  i  hour  to 
.4306 
.4287 

5,953,77s 

23  pounds. 

.0098 
.0075 

13,839,806 
13,818,016 
I3,959t5o8 
!3,942»939 
I3,937ii73 

I 

.0215 

.OT94 

13,905,974  ; 
I3i836,74I  I 
13,735,503 
13<,593,199 
13,424,108 

-7°59 
.7014 

4,700,689 

rose. 
120  pounds. 

9,960  (metric 



4,918). 



10,791,095 

STRENGTH  OF  COPPER  ALLOYS. 
TABLE  LXXXIIL— Continued. 

BAR    NO.     89. 

COMPOSITION.— Original  mixture  :  Cu,  85  ;  Sn,  12.5  ;  Zn,  2.5. 


475 


LOAD. 

Pounds. 
3 

10 
20 

£ 

120 
1  60 
200 
10 

3 

200 
240 
280 

$ 

400 
10 

3 

400 
440 
480 
520 

& 

600 

10 

6oi 

640 
680 
720 
760 
800 

10 

Soi 

840 
880 
Q20 
060 

1,000 
10 

3 

1,000 

1,040 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

LOAD. 

DEFLECTION. 

SET. 

MODULUS  OF 
ELASTICITY. 

Inch. 

.0021 

.0067 

.0112 
.0207 
.0292 
.0367 
.0444 

.0450 
•0536 
.0620 
.0694 
.0765 
.0840 

!o84; 
.0915 
.0981 

.1^55 
.1131 
.1208 

.1210 
.1279 
.1352 
.1427 
.1504 
•1594 

!ieo6 
.1692 
.i798 
•  1930 
.2095 
.2265 

.2307 
.2460 

Inch. 

Pounds. 
i,  080 

1,120 

1,160 

1,200 
10 

3 

1,200 
1,240 
1,280 

Inches. 
.2647 
.2880 
•3193 
•  3505 

Inch. 

.0031 
.0010 

.0053 
.0031 

7,877,604 
9,424,989 
10^99,024 
10,845,190 
H,505,l64 
11,886,372 

•  1245 
.1214 

9,035,081 

•  3625 
•3993 
•  4435 
.5130 
.5783 
.6527 

11,816,403 
11,918,049 
12,168,285 
12,419,811 
12,566,652 

x'jfio 
1,400 

10 

3 
1,400 
1.440 
1,480 
^520 

'»£ 

i,  600 

10 

3 
1,600 

% 

,720 
'740 
,760 
,78o 
,800 
,820 
,840 
,860 
,880 

1,000 

1,920 

The  bear 
crease 
Breaking 
Modulus 

J 

•  3707 
.3671 

5,660,481 

•6743 
.7230 
.8345 
•  9425 
.0777 
.2199 

.2255 
•3M5 

''Si 

•9655 
•0745 
.1805 
•2995 
•4075 

:lg 

.8285 
Q  could  not 
of  load. 
load,/'=i, 
of  rupture, 

'=£  =  • 

:8472 
.8423 

3,461,264 

ioos; 
.0049 

12,690,260 
12,915,497 

13'°°2'i77 
13,066,650 
13,107,604 

.0172 
.0143 

13,205,304 
13,273.061 
131315*159 
13*335,359 
13,244,652 



2,257,161 



13,101,403 

be  raised  with  an  in- 
920  pounds. 

2,405  (metric,  4,387). 

.0438 
.0410 

11,651,201 

CHAPTER   XIII. 

CONDITIONS  AFFECTING   STRENGTH   OF   NON-FERROUS 
METALS   AND   ALLOYS. 

268.  The  Conditions  Affecting  the  Strength  of  the  Non- 
Ferrous  Metals  are   precisely  such  as  have  been   found  to 
modify  the  valuable  properties  of  iron  and  steel,  and  of  other 
materials  of  construction   used  by  the  engineer.     The  effect 
of  every  change,  whether  chemical  or  physical,  of  internal  or 
of  external  conditions,  affecting  the  metal  is  seen  in  a  modifi- 
cation   of   its    strength,    elasticity,    ductility   and    resilience. 
Change  of  temperature,  either  gradual  or  sudden,  alteration 
of  methods  of  manufacture,   differences,  however  slight,   of 
composition  and  of  density,  and  every  variation  of  the  mag- 
nitude, and  of  the  number  of  applications,  of  the  load  has  an 
effect,  more  or  less  marked  and  important,  upon  the  value  and 
reliability  of  the  metal  as  a  structural  material. 

The  effect  of  heat  and  of  variation  of  temperature  upon 
the  non-ferrous  metals  and  upon  the  alloys  has  been  but 
little  studied ;  but  some  important  facts  have  become  well 
ascertained. 

269.  The  Strength  of  Copper  is   modified    by  tempera- 
ture in  the  same  general  way  as  iron  (Part  II.,  Arts.  285-288). 
It  is  reduced  steadily,  and  according  to  a  simple  law,  as  tem- 
perature rises,  finally  becoming  zero  at  the  point  of  fusion. 
Decrease  of  temperature  causes  increase  of  strength. 

A  committee  of  the  Franklin  Institute,  of  the  State  of 
Pennsylvania,  consisting  of  Professor  W.  R.  Johnson,  Benja- 
min Reeves,  and  Professor  A.  D.  Bache,  were  engaged,  during 
a  period  extending  from  April,  1832,  to  January,  1837,  in 
experiments  upon  the  tenacity  of  iron  and  of  copper,  under 
the  varying  conditions  of  ordinary  use. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS,      477 

The  effect  of  change  of  temperature  upon  those  metals 
was  investigated  with  equal  intelligence  and  thoroughness, 
and  most  valuable  results  were  obtained. 

Upward  of  one  hundred  experiments  upon  copper,  at 
temperatures  ranging  from  the  freezing  point  up  to  1,000° 
Fahrenheit,  exhibited  plainly  the  fact  that  a  gradual  diminu- 
tion of  strength  occurs  with  increase  of  temperature,  and  vice 
versa,  and  that  the  change  is  as  uniform  as  the  unavoidable 
irregularities  in  the  structure  of  the  metal  would  allow. 

The  law  of  this  variation  of  tenacity,  within  the  limits 
between  which  the  experiments  were  made,  was  found  to  be 
closely  represented  by  the  formula, 

D*  =  C  T3, 

i.  e.,  the  squares  of  the  diminutions  of  tenacity  vary  as  the 
cubes  of  the  observed  temperatures  measured  from  the  freez- 
ing point. 

The  following  are  the  tenacities  of  copper  at  various 
temperatures,  as  determined  by  experiment,  to  the  nearest 
round  numbers : 

TABLE  LXXXIV. 

TENACITIES   OF   COPPER   WITH   VARYING    TEMPERATURES. 


TEMPERATURE. 

TENACITY. 

TEMPERATURE. 

TENACITY. 

F. 

C. 

Lbs.  per 
sq.  in. 

Kilogs.  per 
sq.  cm. 

F. 

C. 

Lbs.  per 
sq.  in. 

Kilogs.  pei 
sq.  cm. 

122° 

50° 

33,000 

231 

602° 

316° 

22,000 

212 

100 

32,000 

225 

801 

427 

19,000 

144 

302 

150 

31,000 

218 

912 

490 

15,000 

105 

482 

250 

27,000 

190 

I  016 

546 

11,000 

77 

545 

290 

25,000 

176 

2,032 

i,ni 

o 

0 

270.  The  Effect  of  Heat  on  Bronze  and  the  kalchoid  al- 
loys of  copper,  tin  and  zinc  was  determined  by  the  British 
Admiralty  at  Portsmouth  in  the  year  1877.* 


*  London  Engineering,  Oct.  5,  1877, 


478  MATERIALS  OF  ENGINEERING—NON-FERROUS  METALS. 

The  metal  was  cast  in  the  form  of  rods  one  inch  in 
diameter,  and  composed  of  five  different  alloys  as  follows : 

No.  i.  Copper,  87.75  ;    tin   9.75;  zinc,  2.5. 

No.  2.  Copper,  91  ;  tin,  7     zinc,  2. 

No.  3.  Copper,  85  ;  tin,  5     zinc,  10. 

No.  4.  Copper,  83  ;  tin,  2     zinc,  15. 

No.  5.  Copper,  92.5  ;  tin,  5  ;  zinc,  2.5. 

The  specimens  were  heated  in  an  oil  bath  near  the  test- 
ing machine,  and  the  operation  of  fixing  and  breaking  was 
rapidly  and  carefully  performed,  so  as  to  prevent,  as  far  as 
possible,  loss  of  heat  by  radiation.  The  strength  and  ductility 
of  the  above  test-pieces,  at  atmospheric  temperature,  were  as 
follows:  No.  I,  535  pounds,  12.5  percent.;  No.  2,  825  pounds, 
16  per  cent.;  No.  3,  525  pounds,  21  per  cent.;  No.  4,  485 
pounds,  26  per  cent,  and  No.  5,  560  pounds,  20  per  cent.  As 
the  heat  increases  a  gradual  loss  in  strength  and  ductility 
occurs,  up  to  a  certain  temperature,  at  which,  within  a  few 
degrees,  a  great  change  takes  place,  the  strength  falls  to 
about  one  half  the  original,  and  the  ductility  is  wholly  gone. 
Thus  in  alloy  No.  I,  at  400°  F.  (204°  C.)  the  tensile  strength 
had  fallen  to  245  Ibs.,  and  the  ductility  to  0.75  per  cent.  ;  the 
precise  temperature  at  which  the  change  took  place  was 
ascertained  to  be  about  370°  F.  (188°  C.).  At  350°  F.  (177° 
C),  the  tensile  strength  was  450  Ibs.,  and  ductility  8.25  per 
cent.  At  temperatures  above  the  point  where  this  change 
begins  and  up  to  500°  F.  (260°  C.)  there  is  little  if  any  loss  of 
strength. 

Phosphor-bronze  was  less  affected  by  heat,  and  at  500°  F. 
(260°  C.)  retained  two-thirds  its  tenacity  and  one-third  its 
ductility.  Muntz  metal  (copper,  62;  zinc,  38)  was  found 
reliable  up  to  the  limit,  and  iron  and  steel  were  not  injured. 

The  following  table  exhibits  the  results  of  these  experi- 
ments in  convenient  shape. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLO  YS.      479 


w 


i 

OS 


ioio<><j,  »o      «*      w*      £ 

^       .o 

"v*  ••  IQ        •        •        •        • 

£       w        '•        IS*0 

4j      vo^       •        •      •«•     >£      10       •        •        •        • 

K         VO         <G          «O       «"         WJ          fO         1O         «O         M        'Q 

^<5.°5.¥^.???5^>^ 
"5  >o  «* 

^       M^2       2>O>«doo       »^«       ci       ei 

»;iOOOfOiOMioOOO 
^J       "loRJoioio^ci       e?« 

u      ."?...-;;    s:          ~ 
tvS^?°SM"fl      ;c          '5 

I    a?     :     :    «?    ^     :    a     :  : 

*;       «0        ;     '    ;       »J>      w»      «       g> 

J^          «0  |  j          10         fO         M  M  •  | 

^          «  ^         K 

k        «        O        M        O        O        O       00 

$ 


tit  r 


s  I 

HN 


o.=  « 

UHN 


UHN 


HS 


o       10100 

^S-V8     JT 


t     Its     ft    8     S>    8     ft    8     S.    8 

•c-      -C*^  M       •<       <i       M       ft*   *(     Jr     «r     • 


480  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

271.  Various  Metals. — Variations  of  temperature,  accord- 
ing to  Baudrimont,*  produce  alterations  of  the  tenacity  of 
metals,  as  below.  The  metals  were  in  the  form  of  wire, 
nearly  0.4  millimetre  (0.0158  inch)  in  diameter,  except  the 
iron,  which  was  0.175  mm.  (0.0067  inch),  and  the  copper, 
0.48  mm.  (0.0189  inch).  The  tenacity  is  reduced  to  kilo- 
grammes per  square  centimetre.  All,  except  iron,  are  weak- 
ened by  increase  of  temperature. 

TABLE   LXXXVI. 

TENACITIES   OF   METALS  AT  VARYING   TEMPERATURES. 


TENACITY    IN   KILOGS.   PER    SQ.    CM. 

o°  C.  (32°  F.) 

100°  C.  (212°  F.) 

200°  C.  (392°  F.) 

Gold 

1,840 
2,263 
2,510 

2,832 
3,648 
20,540 

1,522 
1,928 
2,187 
2,327 
3,248 
19,173 

1,288 
1,728 
1,822 
1,858 
2,708 
21,027 

Platinum 

Copper.  . 

Silver 

Palladium 

Iron  

272.  The  Modulus  of  Elasticity  of  hard-drawn  iron,  cop- 
per. and  brass  wires  was  found  by  Loomis  and  Kohlrausch  f 
to  vary  with  temperature  according  to  a  law  expressed  by 
the  equation 


in  which  E  is  the  modulus  at  the  temperature  /,  E0  that  at  o° 
and  a  and  b  experimentally  determined  co-efficients  ;  for  the 
Centigrade  scale,  their  values  are 


a 

b 

Iron  

o  0004.8^ 

O  OOO  OOO  12 

Copper.  . 

o  ooo  572 

o  ooo  ooo  28 

Brass  

o  ooo  48^ 

o  ooo  ooi  36 

*  Annales  de  Chimie  et  de  Physique,  1850. 

f  Am.  Jour.  Science  and  Arts,  vol.  1.,  Nov.,  1870. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      481 

Thus,  the  reduction  of  the  value  of  the  modulus  between 
the  melting  point  of  ice  and  the  boiling  point  of  water  is,  for 
iron  4.6  to  5  per  cent.;  for  copper,  5.5  to  6  per  cent.;  for  brass, 
5.6  to  6.2  per  cent.,  and  this  variation  is  most  rapid  at  the 
highest  temperature.  The  values  of  the  moduli  were  found 
to  be  very  closely  proportional  to  the  co-efficients  of  expansion. 

The  following  determinations  were  made  by  Wertheim : 


TABLE  LXXXVII. 


VARIATION   OF  MODULI  OF   ELASTICITY   WITH   TEMPERATURE. 


S   G. 

15°  C. 

,  59°  F. 

100°  C. 

,  212°  F. 

200°  C 

.,  392°  F. 

Metric. 

British. 

Metric. 

British. 

Metric. 

British. 

Lead 

n  232 

17-7 

2   J. 

16-? 

2  3 

Gold  

18  0^5 

558 

7.Q 

e-Ji 

7.6 

c,4S 

7  O 

Silver  

10  .  304 

7is 

IO.2 

727 

10.4 

637 

9.  i 

Palladium 

ii  225 

O7Q 

14   O 

CoDDer 

8.0^6 

I  O^2 

ic    o 

Q8-* 

M.o 

786 

II.  2 

Platinum 

<-••  yj>« 
21    083 

I   552 

22    2 

V°J 
I  418 

20    ^ 

I  2o6 

l8    5 

Steel  (wire) 

7  622 

1.728 

24.   Q 

2  I2Q 

-3Q     4 

I.Q28 

27    5 

Steel  (cast) 

7.QIQ 

I  Q56 

26  5 

I.QOI 

27    I 

I  7Q2 

25    6 

Iron  

7.757 

2.O7Q 

26.8 

2,188 

31.2 

I,77O 

25.2 

The  metric  values  are  in  thousands  of  kilogrammes  per 
square  centimetre;  the  British  in  millions  of  pounds  per 
square  inch. 

273.  The  Stress  produced  by  Change  of  Temperature 
is  easily  calculated  when  the  modulus  of  elasticity  and  the 
coefficient  of  expansion  are  known,  thus : 

Let  E  =  the  modulus  of  elasticity ; 

A  =  the  change  of  length  per  degree  and  per  unit  of 

length ; 

Af  —  the  difference  of  initial  and  final  temperatures; 
/  —  the  stress  produced. 
31 


482  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Then: 

/  :  E  :  :  A  Af  :  i, 

.-./  =  \EAf (i) 

For  good  wrought  iron  and  steel,  taking  E  as  28,000,000 
pounds  on  the  square  inch,  or  2,000,000  kilogrammes  on  the 
square  centimetre,  and  A.  as  o.  0000068  for  Fahrenheit,  and  as 
0.0000120  for  Centigrade  degrees  : 


—  190  Af  Fahr.,  nearly  } 


.      .      .      .      (2) 


=     25  At0  Cent.,  nearly  ) 
For  cast  iron,  taking  E  =  16.000,000;  1  =  0.0000062 : 


p  —  100  Af  Fahr.,  nearly  ,  ,  , 

=     12  Af  Cent.,  nearly  '       '     ' 


This  force  must  be  allowed  for  as  if  a  part  of  the  tension, 
T,  or  compression,  C,  produced  by  the  working  load  when 
the  parts  are  not  free  to  expand. 

274.  Sudden  Variation  of  Temperature  has  an  effect, 
very  usually,  upon  the  non-ferrous  metals,  which  is  afterward 
seen  in  a  permanent  alteration  of  their  properties.  Repeated 
heating  and  cooling  causes  a  permanent  change  of  form,  and 
sudden  cooling  from  high  temperatures  causes  a  modification 
of  the  tenacity  and  ductility  of  the  kalchoids  and  the  metals 
composing  such  alloys,  which  is  precisely  the  opposite  of  that 
produced  on  steel.  Thus  copper,  brass,  and  bronze,  suddenly 
cooled  from  a  low  red  heat,  are  softened  and  weakened  and 
greatly  improved  in  malleability  and  ductility.  This  process, 
which  is  one  of  hardening  and  tempering  with  steels,  is  thus 
one  of  softening  with  other  metals.  On  the  other  hand,  very 
slow  cooling  softens  or  "  anneals  "  steels,  while  it  hardens  the 
non-ferrous  metals  and  alloys.  Thus,  also,  casting  bronze  ord- 
nance or  other  castings  in  chills  increases  the  value  of  the 
metal  by  preventing  liquation  and  securing  homogeneousness 
and  maximum  density. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      483 

275.  The  Effect  of  Chill-casting  is  exhibited  in  the  fol- 
lowing tables  of  tests  by  tension  furnished  to  the  Author  by 
the  U.  S.  N.  Department  in  the  course  of  a  series  of  investi- 
gations in  1877.  The  metal  has  the  composition,  copper  (Lake 
Superior),  9 ;  tin,  I  ;  it  was  cast  either  in  chills  or  in  sand  as 
specified,  after  having  been  melted  in  a  reverberatory  furnace, 
the  copper  first  and  the  tin  three  hours  later.  The  specimens 
tested  were  of  the  "  short "  pattern,  and  the  reduction  of  sec- 
tion, rather  than  the  elongation  recorded,  is  the  measure  of 
relative  ductility.  The  tables  also  exhibit  the  method  of 
testing  usual  in  the  Ordnance  Department  of  the  U.  S.  Navy 
in  1875-6.  British  measures  are  here  used. 


TABLE  LXXXVIII. 

EFFECT   OF   CASTING   BRONZE   IN    "CHILLS.' 

Navy  Ordnance- Bronze. 


TENSILE 

I   b. 
O        98 

i~i 

STRENGTH    PER 

Z  cr.  H 
OHO 

S   w   R 

g 

SQUARE  INCH  OF— 

S«g 

Sgs 

H 

MARK. 

S  - 

H        , 

<! 

bfch 

> 

13  . 

lc 

Is! 

H  °  ° 

O 

y 

sl 

0* 

fl 

<  Z  C 

S£2 

£HC 

l«i 

SPECIF] 

Mi,  3-4-75  
M  2.  ^-4-75  
BB  IX 

£3 

22,385 

70,000 
71,600 

.100 

.40 
•417 

Full  of  large  tin  spots. 

M  2,  5^75  
No.  3,  8-21-75  .. 
No.  2,  8-21-75  .. 

45,737 
49,772 
48,000 

65,600 
60,000 

.2603 

.211 

•470 
.240 

.20 

8  878 

Cast  in  chill  mould. 
Cast  in  chill  mould. 

GB  2,  5-6-75... 
GB  3,  5-6-75  •  •  • 
R  3  L,  12-70-7=;. 
M  i  C,  3-11-76  . 
B  2  C,  3-11-76.. 
B  3  C,  3-11-76.. 

lg]8rt 
5i'v459 

39,000 
91,600 
73,450 
71,600 

•4075 
.0291 

!s8o 
.396 
•  415 

•50 

.438 
.376 

•373 

8  392 
8853 

Flaw  in  the  breaking  portion. 
Cast  in  chill  mould. 

(.ast  in  chill  mould. 
Cast  in  chill  mould. 

The  guns  cast  in  chill  moulds  were  composed  of  10  parts 
of  copper  to  I  part  of  tin  ;  the  others  were  of  o  parts  of  cop- 
per to  i  part  of  tin. 

In  the  course  of  experiments  made  by  Major  Wade,*  three 


*  Report  on  Ordnance. 


484  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

howitzers,  Nos.  27,  28,  and  29,  were  cast  from  the  same  liquid 
metal.  No.  27  was  cast  when  the  metal  was  at  the  highest 
temperature,  No.  28  was  cast  fifteen  minutes  later,  and  No. 
29  fourteen  minutes  after  No.  28.  The  following  results  were 
obtained : 


K 

s 

Z 

27 

28 

»9 

TIME  OF  METAL  IN 
LADLE,  MINUTES. 

TEMPERATURE  OF 
METAL  AT  CASTING. 

SPECIFIC    GRAVITY  — 

TENACITY— 

Of  gun- 
heads. 

Of  entire 
gun. 

Of  small  bars  cast 
in— 

Of  gun- 
heads. 

Of  small  bars  cast 
in— 

Gun 

mould. 

Separate 
mould. 

Gun 
mould. 

Separate 
mould. 

O 

15 
29 

Highest  .  .  . 
Mean  
Lowest  

7.986 
8.351 
8.538 

8.195 
8.551 
8.752 

8.686 
8.823 
8.816 

8.554 
8.447 
8.376 

17,761 
28,995 
23,722 

50,973 
52,330 
56,786 

31,^32 

28,153 
28,082 

In  casting  another  howitzer,  No.  30,  small  test-bars  were 
cast  in  separate  moulds,  one  of  which  was  of  cast  iron,  to 
ascertain  the  effect  of  sudden  cooling,  and  the  others  were  of 
clay,  similar  to  the  gun-mould.  The  tests  of  all  the  samples 
from  this  casting  were  as  follows : 


SPECIFIC  GRAVITY. 

TENACITY. 

Small  bars  cast  separately  in  iron  mould.  . 
Small  bars  cast  separately  in  clay  mould.  . 
Small  bar  cast  in  gun  mould  

8-953 
8.313 
8.806 

37,688 
25,783 

C7    708 

Gun-head  samples  

8    J.QO 

qc   £78 

Finished  howitzer  

8.  T\II 

The  effect  of  the  chill  is  evidently  very  beneficial,  and  iron 
moulds  should,  therefore,  always  be  used  where  possible  in 
the  casting  of  bronze  ;  with  brass  they  are  less  necessary. 

276.  Effect  of  Tempering  and  Annealing. — Riche  de- 
termined the  effect  of  tempering  and  annealing  upon  the 


CONDI TIONS  A FFE C  TING  S  TRENG  TH  OF  ALLO  YS.      48  5 

density  of  the  bronzes,  finding  that  tempering  increased  the 
density  of  those  rich  in  tin  but  not  of  others,  as  gun-bronzes ; 
and  that  annealing  reduces  the  density  of  tempered  bronze 
although  it  does  not  entirely  destroy  that  effect.  Density  is 
increased  to  a  considerable  degree  by  mechanical  action  as 
well  as  by  tempering. 

Successive  temperings  and  annealings  produce,  on  the 
whole,  an  increase  of  density.  Tempering,  according  to  both 
Darcet  and  Riche,  softens  the  bronzes  rich  in  tin,  i.e.,  those 
containing  about  20  per  cent.  tin.  Thus,  Riche  obtained  the 
result  that  such  bronzes,  tempered,  can  be  moulded  in  the 
press,  while  they  will  crack  if  untempered  or  annealed. 
Bronze  and  steel  exhibit  opposite  behavior  in  this  respect. 
The  same  author  finds  that  working  hot  does  not  increase 
the  density  more  than  working  at  low  temperature.  The 
metal  increases  in  density  very  rapidly  by  working  hot, 
and  without  danger  of  rupture ;  while  cold  the  action  is  ex- 
tremely slight  and  very  difficult. 

There  is  evidence  that  the  method  of  making  gongs  by 
the  Chinese  involves  working  hot  under  the  hammer.* 

Riche,  reaches  the  following  conclusions :  f 

"The  bronzes  rich  in  tin  (18  to  22  per  cent.)  increase  in 
density  with  tempering;  and  annealing  lessens  the  density  of 
tempered  bronze,  but  in  a  less  proportion.  The  density  is 
considerably  increased  by  the  alternate  actipn  of  tempering 
and  annealing,  and  of  the  press.  These  effects,  tne  reverse 
of  those  in  steel,  coincide  with  the  fact  that  tempering  softens 
bronze  while  it  hardens  steel. 

"  This  softening,  discovered  by  Darcet,  is  not  sufficient 
to  allow  of  this  bronze  being  worked  cold  for  industrial  pur- 
poses. It  was  shown  that  this  metal — extremely  hard  when 
cold  and  pulverizable  at  red  heat — is  forged  and  rolled  at 
dark  red  heat  with  remarkable  facility.  This  fact  enabled 
me,  in  common  with  M.  Champion,  to  succeed  in  the  manu- 
facture of  tamtams,  and  other  sonorous  instruments,  by  the 
method  followed  in  the  East. 

*  Industries  Anciennes,  etc.     Lacroix,  Paris,  1869. 
\  Annales  de  Chimie  et  de  Physique,  vol.  xxx.,  1873. 


486   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

"  Tempering  produced  no  apparent  softening  in  the 
bronzes  less  rich  in  tin  (12  to  6  per  cent.);  and  if  they  are 
tempered  for  industrial  uses  it  is  more  especially  in  order  to 
detach  the  oxide  produced  during  the  reheating  of  the  matter 
in  the  course  of  the  operations. 

"  It  was  found  that  in  the  axis  of  a  cannon,  and  especially 
toward  the  muzzle,  there  are  some  parts  very  rich  in  tin  and 
in  zinc. 

"  The  density  of  copper,  subjected  alternately  to  me- 
chanical action,  then  to  tempering  or  annealing,  displays  in- 
verse variations  according  as  it  is  exposed  to  the  air  or 
sheltered  from  it  during  the  reheating;  while  in  the  first  case 
the  mechanical  action  increases  the  density,  in  the  second 
mechanical  action  diminishes  the  density. 

"  Mechanical  action*  increases  the  density  of  yellow  brass, 
and  this  effect  is  counteracted  in  part  by  tempering,  and 
especially  by  annealing.  It  is  thought  that  annealing  is  pref- 
erable to  tempering  in  working  with  brass. 

"  Mechanical  action,  tempering,  and  annealing,  do  not 
sensibly  change  the  volume  of  similor  and  of  the  bronzes  of 
aluminium,  alloys  remarkable  for  the  facility  with  which  they 
can  be  worked. 

"  While  repeated  mechanical  action  increases  the  density 
of  the  bronzes  rich  in  tin,  especially  of  porous  copper,  of 
copper  alloyed  with  iron,  of  brass,  it  evidently  diminishes  the 
density  of  copper  exposed  to  the  air  during  reheating,  and  it 
produces  no  noticeable  alteration  in  the  volume  of  similor  or 
of  aluminium  bronze.  Tempering  produces  on  brass,  and 
especially  on  the  bronzes  rich  in  tin  previously  annealed,  an 
increase  in  density,  contrary  to  what  takes  place  in  steel,  cop- 
per and  glass. 

"  It  will  be  perceived  that  tempering  diminishes  the 
density  of  a  body,  because  the  surface,  cooled  before  the 
centre,  cannot  contract  freely  by  reason  of  the  resistance 
that  the  interior  parts  dilated  at  this  moment  offer  to  con- 
traction." 

The  following  are  some  of  the  results  of  Riche's  experi- 
ments. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      487 


BRASS. 

DEN 

SITY. 

I. 

II. 

After  rolling  

8.4OQ 

8   412 

After  tempering  

8  410 

8    /ITT 

After  rolling  

8  4i4 

8    4IS 

8.4-11 

8427 

After  rolling  

U..+JJ. 

8   447 

8  416 

After  tempering  

8  433 

o.^ju 
8416 

8  410 

84/M 

8.4-37 

8   417 

After  rolling  

8  .no 

8417 

After  tempering  

8   44^ 

8    441 

The  metal  was  a  yellow  brass  containing  copper,  65  ;  zinc, 
35.  The  same  general  effect  was  seen  when  the  brass  con- 
tained, copper,  91  ;  zinc,  9. 

It  is  to  be  noted  that  there  is  a  great  difference  between 
the  effect  on  copper  protected  from  the  air  while  heating  it, 
as  should  always  be  done,  and  on  copper  exposed  to  the  air ; 
annealing  and  tempering  diminished  density  in  the  one  case 
and  increased  it  in  the  other,  although  the  latter  modification 
is  not  important.  The  increase  of  density  resulting  from  the 
heat  is  very  nearly  compensated  by  the  tempering,  so  that 
the  plate,  after  being  made  considerably  thinner,  is  found  to 
have  the  same  density  as  before  the  operation.  Cast  at  a 
high  temperature,  the  density  became  8.939,  in  Riche's  ex- 
periments, and  was  but  8.039  when  poured  at  a  low  heat. 

277.  The  Effect  of  Annealing  on  Tenacity  is  seen  in 
the  following  experiments : 

Wertheim  obtained  for  the  tenacity  of  copper  wire, 


T. 

Tm. 

ELON. 

58,600 

4,100 

0.0033 

45,100 

3,160 

0.0030 

488  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Kirkaldy,  testing  wire,  obtained  the  following  results : 

TABLE    LXXXIX. 

TENACITY   OF   WIRE,    HARD   AND   ANNEALED. 


COMPLETE  TURNS 

<  H 

HARD    WIRE   (A). 

ANNEALED  WIRE  (E). 

IN    5    IN.    (12.8 

gfl 

CM.). 

0^ 

^ 

Lbs.  per 

Kilogs. 

Lbs.  per 

Kilogs. 

A. 

B. 

^ 

sq.  in. 

persq.  cm. 

sq.  in. 

per  sq.  cm. 

E  h 

Phosphor-bronze  . 

102,750 

7,224 

49*351 

3-470 

6.7 

87 

37-5 

i            « 

120,957 

8,504 

47,787 

1,360 

22.3 

52 

34-1 

f            a 

120,950 

8,503 

53,381 

3-753 

13.0 

124 

42.4 

'             *l 

139,141 

9,872 

54,153 

3,807 

17-3 

53 

44-9 

i            t( 

159.515 

11,212 

58,853 

4,138 

13-3 

66 

46.6 

'             " 

i5i,H9 

IO,625 

64.569 

4.340 

15-8 

60 

42.8 

Copper. 

63  1  22 

A    A  OS 

•77  002 

2  6O2 

86.7 

96 

34-i 

Steel 

1  2O  076 

8  506 

74.  6^7 

5,248 

22.4 

79 

10.9 

Best  charcoal  iron. 

65,834 

4,629 

46,160 

3,245 

48.0 

87 

28.0 

These  figures  are  considerably  in  excess  of  those  or- 
dinarily obtained  for  bronzes  into  which  no  phosphorus  has 
been  introduced.  The  effect  of  annealing  is  remarkably  great. 

Other  illustrations  of  this  and  related  phenomena  are 
given  elsewhere,  as,  e.g.,  in  Art.  247,  where  they  are  well  ex- 
hibited in  Anderson's  experiments  on  sterro-metal. 

278.  The  Effect  of  Temperature  of  Casting  and  cool- 
ing upon  zinc  has  been  studied  by  Bolley  as  illustrative  of 
this  effect  generally.*  He  finds  that  zinc  may  solidify  in 
either  of  two  forms,  the  one  finely  crystalline,  the  other 
coarsely  crystalline  with  lamellar  structure.  He  finds  these 
conditions  to  be  determined,  not  by  the  presence  of  other 
elements,  but  by  the  temperature  of  casting.  When  cast  at 
the  lowest  temperature  at  which  it  will  "  pour,"  it  takes  the 
first  form,  v/ith  a  density  of  7.18;  when  cast  at  a  full  red 
heat,  it  takes  the  second  form,  with  a  lower  density,  6.86. 
In  the  first  case,  it  is  comparatively  malleable,  remains  malle- 
able throughout  a  wide  range  of  temperature,  and  is  not  as 
readily  soluble  in  acids  as  when  in  the  second  condition.  In 


*  Annalen  der  Chimie  und  Pharm.,  xcv,,  p.  294. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      489 

the  latter  form  it  is  not  malleable,  and  is  more  soluble. 
These  conditions  have  not  been  studied  with  other  metals. 

279.  The  Effect  of  Time,  and  Velocity  of  Rupture,  on 
the  action  of  stress  is  not  less  important  with  the  non- 
ferrous  than  with  the  ferrous  metals.  A  very  important 
difference  is  found  to  exist  between  the  two  classes.  (See 
Part  II.,  Art.  295,  et  seg.)  The  rupture  of  the  non-ferrous 
metals  takes  place  under  lower  stresses,  as  the  time  of  oper- 
ation is  greater,  and  the  fracture  is  more  slowly  produced. 
The  contrary  is  the  case  with  iron  and  steel.  With  non-ferrous 
metals,  the  piece  strained  may  give  way,  ultimately,  under 
static  loads  greatly  less  than  those  required  to  produce  im- 
mediate rupture.  This  occurs  to  a  less  extent  with  soft 
annealed  iron,  and  still  less  with  harder  irons  and  steels. 
Cast  iron  is  stated  by  Hodgkinson  to  be  capable  of  sustain- 
ing, indefinitely,  loads  closely  approaching  the  breaking  load 
under  test.  Some  of  the  alloys  will  probably  exhibit  similar 
differences. 

With  rapid  distortion,  the  resistance  is  increased  with 
non-ferrous  metals,  decreased  with  iron. 

The  Author  has,  therefore,  enunciated  a  principle  which 
had  been  deduced  from  experiments  on  wrought  iron,  which 
is,  evidently,  of  vital  importance  to  the  engineer,  viz.  :  "  That 
the  time  during  which  applied  stress  acts  is  an  important  ele- 
ment in  determining  its  effects,  not  only  as  an  element  which 
modifies  the  effect  of  the  vis  viva  of  the  attacking  mass  and 
the  action  of  the  inertia  of  the  piece  attacked,  but  also  as 
modifying  seriously  the  conditions  of  production  and  relief 
of  internal  strain  by  even  simple  stresses."  * 

Should  it  be  true,  as  suggested  by  the  Author,  that  the 
cause  of  the  variation  of  resistance,  sometimes  observed  with 
increased  velocity  of  distortion,  is  closely  related  to  the  cause 
of  the  variation  of  the  elastic  limit  by  strain,  f  it  would  seem 
to  be  a  corollary  that  materials  so  inelastic  and  so  viscous  as 
to  be  incapable  of  becoming  internally  strained  during  dis- 
tortion, should  offer  greater  resistance  to  rapid  than  to 

*  Trans.  American  Society  of  Civil  Engineers,  vol.  iv.,  p.  334. 
f  See  Part  II.,  pp.  588-604;  figures  135-138. 


•UNIVERSITY 


490  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

slowly-produced  distortion,  in  consequence  of  their  inability 
to  "  flow  "  so  rapidly  as  to  reduce  resistance  by  such  fluxion 
at  the  higher  speed,  or  by  correspondingly  reducing  the 
fractured  section.  This  principle  has  been  shown,  by  a  large 
number  of  experiments,  to  be  frequently,  if  not  invariably, 
the  fact.  Copper,  tin,  and  other  inelastic  and  ductile  metals 
and  alloys,  were  found  by  the  author  to  exhibit  this  behavior, 
and  are  therefore  quite  opposite  in  this  respect  to  commercial 
wrought  iron  and  worked  steel. 

The  records  of  the  Mechanical  Laboratory  of  Sibley  Col- 
lege, Cornell  University,  frequently  illustrate  the  proposition 
that  metals  which  gradually  yield  under  a  constant  load  offer 
increased  resistance  with  increased  rapidity  of  rupture. 

The  curves  of  deflections  of  a  considerable  number  of 
ductile  metals  and  alloys  are  very  smooth  when  the  time  dur- 
ing which  each  load  has  been  left  upon  them  is  the  same  ;  but 
whenever  that  time  has  been  variable  the  curve  has  been 
irregular.  Bars  of  such  metals  broken  by  transverse  stress 
give  a  greater  resistance  to  rapidly  increasing  stress  than  to 
stress  slowly  intensified.  Two  pieces  of  tin,  as  described  in 
Article  280,  were  broken  by  tension,  the  one  rapidly  and 
the  other  slowly.  The  first  broke  under  a  load  of  2,100  and 
the  latter  of  1,400  pounds.  The  example  illustrates  well  the 
very  great  difference  which  is  possible  in  such  cases,  and 
seems  to  the  writer  to  indicate  the  possibility,  in  extreme 
cases,  of  obtaining  results  which  may  be  fatally  deceptive 
when  the  time  of  rupture  is  not  noted. 

The  depression  of  the  elastic  limit  has  been  observed  pre- 
viously in  materials,  but  less  attention  has  been  paid  to  it  than 
the  importance  of  the  phenomenon  would  seem  to  demand. 

The  strain  diagram  of  a  bronze  bar  is  nearly  hyperbolic  ; 
but  the  law  of  Hooke,  ut  tensio  sic  vis,  holds  good,  as  usual,  up 
to  a  point  at  which  the  load  is  about  one-half  the  maximum. 
The  curve  of  times  and  loads  exhibits  the  rate  of  loss  of  effort 
while  the  bar  was  finally  held  at  a  deflection  of  0.5456  inch, 
the  load  being  carefully  and  regularly  reduced,  as  the  effort 
diminished,  from  1,233  to  911  pounds,  at  which  latter  figure 
the  bar  broke.  The  curve  is  a  very  smooth  one. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLO  YS.      49! 
TABLE  XC. 

EFFECT  OF  TIME  ON  BRASS. 

BAR    NO.    599. 

90  parts  zinc,  10  parts  copper :  i  x  0.992   x  22  inches. 


i 

| 

i 

LOAD. 

I 

SET. 

LOAD. 

« 

SET. 

LOAD. 

1 

SET. 

z 

h 

a 
a 

§ 

§ 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch. 

23 

0.0033 

363 

0.0781 

_ 

43 

o  0881 

,     $ 

- 

63 

0.0127 

3 

0.0079 

803 

*      •  •  •  • 

103 

0.0225 
0.031 

403 
Resistar 

0.0886 
ce  fell  in  fi 

h.  30  m. 

1,003 
I,IO3 

0.3178 
0.3921 



163 
Resistan 
to  143 

0.0347 
ce  fell  in  i 
0.0347 

5  h  25  m. 

to  333 

o.c886 
0.0896 

0.0246 

I,203 

Resis 

0.481 
ance  fell  i 

0.0039 

Resis 

tance  fell  i 

n  15  h 

163 

0.0391 

to  302 

0.0896 

.5209 

20} 

0.0471 

3°3 

o  0876 

243 

0.0544 

403 

0.1072 

i  233 

0.  HA  tift 

0.0611 

503 

0.1282 

J-TJ 

323 

0.0692 

6o| 

0.1521 



The  bar  was  left  under  strain  at  nh  22™  A.M.,  and  the  effort  to  restore  itself  measured 


at  intervals,  as  follows  : 

HOUR. — 11:37    11:50  A.M.    12:2 
EFFORT. — 1,133    1,093  ^070 

At  ih  23™  P.M.  the  bar  broke. 


12:8 
1,063 


12:25 
1,043 


12:39* 
1,023 


12:53* 
1,003 


12:58*     i:20  P.M. 

993       911  pounds. 


BAR  NO.    596. 

75  parts  zinc,  25  parts  copper  ;  second  casting- ;  0.985  x  0.985  x  22  inches. 


. 

z 

2 

2 

o 

o 

LOAD. 

w 

SET. 

LOAD. 

1 

SET. 

LOAD. 

i 

SET. 

B 

E 

s! 

§ 

H 

Q 

S 

Pounds. 

Inch. 

Inch 

Pounds. 

Inch. 

Inch. 

Pounds. 

Inch. 

Inch 

23 

0.0057 

463 

0.0799 



503 

.0894 

63 

0.0142 

503 

0.0866 



543 

.0952 

. 

103 

0.0207 

3 



0.0014 

583 

.1012 

$ 

0.0275 
0.0346 

5lesiS 

0.0866 
tance  fell 

in  5  h. 

623 

.1042 
.1075 

; 

III 

303 

$ 

423 

0.0414 
0.0485 
0.0549 
0.0610 
0.0669 
0.073 

to  489 

Resistar 
to  473 

3 

0.0866 

o!o866 
ce  fell  in  i 
0.0866 

0.0074 
3  h.  30  m. 
0.0092 

643                  .1102 
663                  .1136 

Broke  5    seconds 
ringing  sound. 

after  with 

An  example  of  somewhat  similar  behavior,  but  exhibited 
by  a  metal  of  very  different  quality,  is  shown  above. 


492  MATERIALS   OF  ENGINEERING— NON-FERROUS  METALS, 

This  bar  was  hard,  brittle,  and  elastic,  but  must  ap- 
parently be  classed  with  tin  in  its  behavior  under  either  con- 
tinued or  intermitted  stress. 

These  latter  specimens  were  broken  ;  one  in  each  set  by 
adding  weight  steadily  until  the  end  of  the  test,  so  as  to  give 
as  little  time  for  elevation  of  elastic  limit  as  was  possible  ; 
and  one  in  each  set  by  intermittent  stress,  observing  sets, 
and  the  elevation  of  the  elastic  limit. 

There  seems  to  the  Author  to  exist  a  distinction,  illus- 
trated in  these  cases,  between  that  "  flow  "  which  is  seen  in 
these  metals,  and  that  to  which  has  been  attributed  the  relief 
of  internal  stress  and  the  elevation  of  the  elastic  limit  by 
strain  and  with  time. 

If  the  long-known  effects  of  cold-hammering,  cold-rolling, 
and  wire-drawing  in  stiffening,  strengthening,  and  hardening 
some  metals  can  be,  as  the  Author  is  inclined  to  believe,  at- 
tributed in  part  to  this  molecular  change,  as  well  as  to  simple 
condensation  and  closing  up  of  cavities  and  pores,  this  vari- 
ation of  the  elastic  limit  by  distortion  under  externally  ap- 
plied force  has  been  shown  to  occur  in  iron  and  in  metals  of 
that  class  in  tension,  torsion,  compression,  and  under  trans- 
verse strain. 

280.  Effect  of  Prolonged  Stress  on  Tin  and  Zinc.— In 
testing  a  bar  of  tin,  in  work  done  as  described  in  earlier  chap- 
ters, the  Author  studied  this  phenomenon.  An  experiment 
on  No.  29  A  (a  bar  of  pure  tin)  was  made  to  determine  the 
difference  in  resistance  to  slow  and  rapid  rupture.  This  bar 
was  a  good  casting,  and  tests  of  the  two  pieces,  one  from  the 
upper  and  one  from  the  lower  end  of  the  bar,  should  show 
little,  if  any,  difference  in  strength.  No.  29  A  was  tested 
with  a  load  of  1,700  pounds,  which  caused  an  elongation  of 
0.15  inch.  This  load  was  then  reduced  to  1,250  pounds,  and 
the  reading  again  taken,  showing  an  elongation  of  0.19  inch, 
which  increased  in  two  minutes  to  0.27  inch.  The  load  was 
then  increased  to  1,400  pounds,  and  the  elongation  was  0.32 
inch.  The  load  was  allowed  to  remain  on  the  bar  for  ten 
minutes,  and  the  elongation  gradually  increased  to  1.7  inches, 
when  the  bar  broke.  It  seems  probable  from  this  test  that 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      493 

the  load  of  1,400  pounds  would  have  broken  the  piece,  even 
if  the  load  of  1,700  pounds  had  not  been  placed  on  it  at  the 
beginning  of  the  test. 


Bar  No.  29  B  was  tested  in  a  different  manner.  The  load 
was  gradually,  but  rapidly,  increased  to  2,100  pounds,  with- 
out stopping  longer  than  was  necessary  to  take  the  reading 


494  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

of  the  elongations  at  975,  1,180, 1,290,  1,600,  and  2,000  pounds. 
At  2,100  pounds,  the  elongation  read  1.88  inches.  The  piece 
then  extended  very  rapidly,  and,  at  the  same  time,  its  resist- 
ance, as  measured  by  the  scale-beam,  reduced  to  1,700  pounds. 
The  pump  of  the  hydraulic  press  was  worked  as  fast  as  pos- 
sible, but  the  beam  could  not  be  balanced  beyond  1,700  pounds. 
The  piece  sustained  this  load  a  few  seconds,  then  broke  after 
an  elongation  of  2.58  inches. 

Comparing  the  tests,  it  is  seen  that  the  resistance  of  No. 
29  A  to  an  elongation  greater  than  0.19  inch  was  never  greater 
than  1,400  pounds,  while  that  of  No.  29  B  was  2,100  pounds, 
or  50  per  cent,  more  than  the  former ;  which  50  per  cent,  ap- 
parent increase  of  strength  was  evidently  due  to  the  greater 
rapidity  of  the  test  of  No.  29  B.  The  fact  that  the  difference 
in  strength  is  only  apparent  is  confirmed  by  the  experiments 
by  torsional  stress  on  pieces  from  the  same  bar.  These 
showed  that  torsion-pieces  No.  29  A  and  No.  29  B,  from  the 
top  and  from  the  bottom  of  the  bar,  tested  by  moderately 
slow  motion,  each  gave  a  resistance  of  14.2  foot-pounds  tor- 
sional moment ;  piece  No.  29  C,  from  the  middle  of  the  bar, 
tested  in  the  same  manner,  resisted  13.2  foot-pounds,  while 
No.  29  D,  a  piece  taken  from  the  middle  of  the  bar  and  ad- 
joining No.  29  C,  tested  by  very  slow  motion  and  left  under 
stress  for  hours,  resisted  only  9.2  foot-pounds  or  some  30  per 
cent,  less  than  either  of  the  other  pieces. 

The  effect  of  slow  and  rapid  test  is  shown  by  both  bars  in 
the  tensile  test.  The  average  tenacity  of  all  the  pieces  tested 
is  given  as  3,130  pounds  per  square  inch,  but  it  is  probable 
that  all  the  pieces  would  have  broken  at  as  low  as  2,000 
pounds  if  the  test  had  been  of  long  duration,  say  one  hour, 
or  as  high  as  4,000  pounds  if  each  test  had  been  made  in, 
say,  five  minutes.  The  records  of  several  tests  follow. 

The  effect  of  time  is  also  shown  in  the  autographic  strain- 
diagrams  (Fig.  30),  and  in  the  records  calculated  from  them. 


CONDITIONS  AFFECTING  STRENGTH  OF  silLOYS.      4Q5 
TABLE   XCI. 

STRENGTH  OF  TIN  AS   VARYING   WITH   TIME  OF  TESTING. 

Tests  by  Tensile  Stress. 

QUEENSLAND   TIN,   CAST. 

No.  58  A.— Material :  Tin  cast  in  iron  mould.    Dimensions  :  Length,  5"  (12.7  cm.)  ; 
Diameter,  0.798"  (2  cm.). 


LOAD  PER  SQUARE 
INCH. 

ELONGATION  IN  5 
INCHFS. 

i 

ELONGATION  IN 
PARTS  OF  ORIG- 
INAL LENGTH. 

LOAD  PER  SQUARE 
INCH. 

ELONGATION  IN  5 
INCHES. 

8 

ELONGATION  IN 
PARTS  OF  ORIG- 
INAL LENGTH. 

Pounds. 

e 

soo 

1,000 

240 

1,200 
1,400 
1,6:0 

1,800 

2,000 
240 

2,000 
2,000  DO 

for  14  mm 
Minutes. 

i 

2 

3 

4 

I 

7 

Inch. 

0.0002 

0.0027 

0.0081 
0.0175 

0.0303 

0-0433 
0.0517 

0.0630 

0.0745 

o!o86o 
unds  per  sqt 
utes,  elongati 

0.1070 
0.1156 
0.1298 
0.1*37 
0.1580 
0.1709 
0.1861 

Inch 
o  0159 

o  0756 

are  inch  ke 
on  increasing 

.00004 
.0005 
.0016 
•0035 

Minutes. 
8 
9 

10 

ii 

Inch. 

0.1997 
0.2176 
0.2328 

0.24(yO 

Pounds. 

.0062 
.0086 
.0103 
.0126 
.0149 

.0172 

3t  constant 
\  as  follows: 

13 
14 
Resistai 
square  int 
side. 
i,703lbs. 
i  min. 
Resistai 
broke  2  in 
The    fr 
boundary 
measured 
Tensile 
section,  u 
kilogs.  pe 
Total  ti 

0.2929 

0-33" 
ice    reduced 
h,  and  a  crac 

0.3610 
0.4315 
ice  decrease 
ches  from  A 
actured    suri 
nearly  ellif 
0.580  and  o.c 
strength  pe 
nder  slow  st 
r  sq.  cm.), 
me  of  test,  3c 



to   1,700  p< 
k  was  obseri 

d  gradually, 
end. 
ace    had  an 
>tical  ;    two 
85  inch. 
r  square  inc 
rain,  2,000  p 

minutes. 

mnds   per 
/ed  on  one 

.0722 
.0863 
and  piece 

irregular 
diameters 

i,  original 
ounds  (141 





No.  58  B. 


400 

0.0005 

.OOOI 

Stress  kept  constant  for  2  minutes. 

600 

O.OO29 

%  m 

,OOo6 

i  mm.    i       0.0724              ......               .0^45 

800 

0.0051 

.0010 

2  min.    I      0.0821             .0164 

1,000 

O.OIOS 

.0022 

Increased  stress  rapidly  for  i  minute,  and 

1,200 

1,400 

0.0184 
0.0293 

•0037 
.0059 

piece  broke  at  3,520  pounds  per  square  inch. 
Total  time  of  test,  8  minutes. 

1,  600 

. 

.0079 

Diameter  of  fractured  section,  0.542  inch. 

1,800 

0.0484 

•0097 

Tensile  strength  per  square  inch,  original 

2,000 

0.0566 

.0113 

section  under  rapid  strain,  3,520  pounds  (248 

240 



0.0557 



kilogs.  per  sq.  cm.). 

2,000 

0.0631 

.0126 

49$  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
TABLE  XCL— Continued. 

TEST   BY    TRANSVERSE    STRESS. 

N0t  58.— Material  :  Queensland  tin  cast  in  iron  mould.— Dimensions :  /  =  22"  (55.9  cm.) ; 
b  —  i"  (.2.54  cm.)  ;    d  —  i"  (2.54  cm.). 


w 

m 

in 

u 

in 

j. 

1 

2 

< 
J 

W 

g 

Z 

w 

II 

s| 

Sg 

II 

ii 

^g 

O  H 
D  3 

™  2 

o  2 

3  H 

PH     M 

52 

J  H 

0 

§ 

z 

o 
J 
H 

H 
M 
in 

o 

O 

Q 

s 

§ 

H 

^ 

en 

Q 
O 

S 

Pounds. 

Inch. 

Inch. 

^««^. 

Inch. 

7«M. 

10 

0.0082 

Resistance  decreased  in  8  minutes  to    56 

20 

0.0118 

5i574i99J 

pounds. 

0009 

100 

0.3033 



10 

0.0087 

no 

0.3827 

O.OI2Q 

I2O 

0.6403 

3° 

0.0173 

5,310,020 

130 

0.8091 



40 

0.0241 

5^35:593 

Cont'd 

f-x-07 

5° 

0.0333 

0126 

3i59  i7  4 

i  min. 

i          7 

60 
70 
80 

0.0502 
0.0600 
0.0859 

140 
till  deflec 

1.36 
Ran  pressi 
.ion  was  mo 

ire-screw  do 
re  than  3  in 

wn  slowly 
ches  ;    the 

o.  1416 

scale-bear 

n  vibratinsr  all  the  time  about  150 

100 

3 

0.2109 

pounds. 
Bent  without  breaking. 

o  1753 

100 

0.2415 

Breaking  load,  P  —  150  pounds. 

Resistance    decreased    in    i    minute    to    70 
pounds. 

Modulus  of  rupture,  R  —  —  VTJJ     =  4?5S9 

Resistance  decreased  in    3    minutes   to    62 
pounds. 

(metric,  321). 

The  effect  of  prolonged  stress  on  cast  zinc  is  exhibited  by 
the  following  memorandum  of  test : 

No.  21  (cast  zinc). — Four  pieces  were  tested  by  torsion, 
which  gave  results  nearly  agreeing,  the  torsional  moments 
varying  from  34.42  to  37.83  foot-pounds,  and  the  angles  of 
torsion  from  123  to  163  degrees.  The  strain  diagrams  of 
these  pieces  exhibit  marked  peculiarities.  No.  21  D  was  left 
for  fourteen  hours  under  stress,  just  before  reaching  its  maxi- 
mum resistance.  In  this  time  the  resistance  decreased  15 
per  cent.  On  resuming  the  test,  the  piece  slowly  resumed 
its  maximum  resistance,  which  it  held  for  some  time.  It  was 
then  left  under  stress,  and  in  about  30  seconds  the  resistance 
decreased  about  15  per  cent.  The  piece  then  broke  partly 
through,  and  the  resistance  decreased  to  less  than  one-half 
the  maximum.  On  continuing  the  torsion,  the  piece  held 
by  the  unbroken  side  exhibited  a  constant  resistance  till  it 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLO  YS.      497 


was  twisted  through  about  80  degrees  further,  when  it  broke 
entirely  across. 

On  No.  21  B  experiments  were  made  to  determine  the 
effect  of  rapid  and  of  slow  stress  and  of  resting  under  stress. 
They  indicated  a  decrease  of  resistance  when  resting  under 
stress,  a  uniform  resistance  to  very  slow  motion,  and  a  rapid 
increase  of  resistance  to  rapid  motion,  except  after  the  resist- 
ance has  reached  the  maximum,  when  rapid  motion  then 
keeps  the  resistance  constant. 

It  was  observed  that  very  ductile  metals,  such  as  tin 
itself  and  alloys  containing  a  large  amount  of  tin,  all  exhibit 
different  amounts  of  resistance  to  slow  and  to  rapid  stress, 
and  a  decrease  of  resistance  on  resting  under  stress.  The 
same  phenomenon  is  exhibited  by  cast  zinc,  which  is  much 
less  ductile  than  the  copper-tin  alloys,  and  is  less  ductile 
than  several  of  the  alloys  of  copper  and  zinc  (those  contain- 
ing from  20  to  40  per  cent,  of  zinc),  which  either  did  not 
show  the  phenomenon  at  all,  or  but  slightly. 

281.  The  Effect  on  Bronze  of  long  continued  stress  in 
producing  continuous  distortion,  even  when  the  loads  are  far 
within  those  required  to  produce  the  same  effect  on  first 
application,  is  well  exhibited  below. 

TABLE  XCII. 

EFFECT  OF  TIME  ON  BRONZE. 

Tests  by  Transverse  Stress— With  Dead  Loads. 
Samples  i  x  i  x  22  inches. 


\ 

MATERIAL   PARTS. 

fr- 
it 
O 

LOAD. 

DEFLEC- 
TION. 

TIME. 

INCREASED 
DEFLEC- 

BREAKING 
WEIGHT. 

6 

"Z 

Tin. 

Copper. 

Pounds. 

Inches. 

Inches. 

Hounds. 

I 

1.9 

100 

08.1 

600 
475 

o-534 
1.762 

5  minutes  .  . 
3  minutes  .  . 

0.009 
0.291 

650 

9 

7.2 

92.8 

S°o 

950 

2.108 
0.348 

3  minutes  .  . 
5  minutes  .  . 

0.488 
0.081 

500 
i,35o 

10 

10. 

90. 

1,485 

o-395 
3-447 

5  minutes  . 
13  minutes  .  . 

0.021 

4.087 

i",485 

ii 

90-3 

9-7 

100 

0.085 

10  minutes  .  . 

0.021 

120 

0.140 

10  minutes  .  . 

0.055 

140 

O.22I 

10  minutes  .. 

0.098 

.... 

140 

o  319 

10  minutes  .  . 

0.038 



I40 

o  357 

40  hours  .  .  . 

0.920 

.... 

32 


MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 
'  TABLE  XCIL— Continued. 


3 

MATERIAL    PARTS. 

| 

k 

LOAD. 

DEFLEC- 
TION. 

TIME. 

INCREASED 
DEFLEC- 

BREAKING 
WEIGHT. 

5 
i 

Tin. 

Copper. 

Pounds. 

Inches. 

Inches. 

Pounds. 

160 

1.294 

10  minutes  .   .  . 

0.025 

160 

1.320 

i  day  

I  .  OOO                     .... 

160 

2.320 

i  day  

I.  000                     

160 

3.320 

i  day  

i.  ooo                160 

2 

98.89 

i.  ii 

90 

0.243 

5  minutes  .    .  . 

0.063             

120 

0.736 

15  minutes  . 

1.055 

120 

1.791 

30  minutes  .    .  . 

0.748           

I2O 

2-539 

45  minutes  

0.595           — 

120 

3-I34 

12  hours  

8.000 

1  20 

3 

100 



80 

0.218 

5  minutes  

0.064 

no 

Metals  having  a  composition  intermediate  between  these 
extremes  have  not  been  observed  to  exhibit  flow  or  to  in- 
crease deflection  under  a  constant  load. 

The  same  phenomena  are  exhibited  by  tests  made  in  the 
autographic  testing  machine,*  thus  : 


\ 

MATERIAL. 

& 

TIME    UNDER 
STRESS. 

OF   TOR- 
SION. 

FALL   OF 
PENCIL. 

REMARKS. 

0 
2 

Tin. 

Cop- 
per. 

0 

tl 

40  hours  .  .  . 

65 

0.06  inch..  . 

Recovered  after  further  distortion  of  i°. 

t? 

100 

i  hour  

,80 

o.i    inch... 

Recovered  in  8°. 

fo 

280 

4 

99-44 

c.S5 

12  minutes  . 

$380 

50  per  cent. 

Did  not  recover. 

98  8i'  i  ii 

6 

Alloy. 

58 

0.2    inches. 

Did  not  recover. 

Tests  by  tension  with  similar  materials  exhibit  similar 
results,  and  these  observations  and  experiments  thus  seem  to 
indicate  that,  under  some  conditions,  the  phenomena  of  flow, 
and  of  variation  of  the  elastic  limit  by  strain,  may  be  co- 
exist^pt,  and  that  progressive  distortion  may  occur  with 
"  viscous  "  metals. 

282.  A  Fluctuation  of  Resistance  with  Time,  illustrated 
in  the  table  here  given,  is  a  singular  phenomenon  which  has 
been  observed  by  the  Author,  but  the  causes  of  which  remain 


Part  II.,  p.  379. 


f  Same  piece. 


Taking  "  elasticity  line." 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      499 
TABLE    XCIII. 

FLUCTUATION    OF    RESISTANCE. 

Test  by  Transverse  Stress. 

ALLOY   OF   COPPER   AND   TIN. 

No.  47.— Material :    Alloy.— Original  mixture:    17.5  O,  82.5  Sn.— Dimensions :    Length 
between  supports,  22'';  Breadth,  0.996";  Depth,  0.983". 


LOAD. 

DEFLEC- 
TION. 
A 

SET. 

MODULUS  OF 
ELASTICITY. 
PP 

LOAD. 

DEFLEC- 
TION. 

A 

SET. 

MODULUS   OF 
ELASTICITY. 
PP 

4  A   Id3 

4  A  bd* 

Pounds. 

10 
20 

40 
60 
80 

IOO 

5 

120 

Ifo 

180 

2OO 

5 

200 
220 
240 
2fo 
270 
280 
200 
300 

Thetx 
reading 

Th?  h 
poise  till 
Time  : 

Inch. 
0.0027 
o  .  0070 
0.0153 
0.0256 

0.0365 
Be 
0.0499 

0.0617 

o.  1042 

0.1343 
0.1666 

Inch. 

In  2 
pounds 
back  ti 
and  anc 
Pounds. 

Beam 
In  2  c 
In  10 
In  39 
Rant 
again  a 

In  4  £ 
In  23 
Inih 
at  20  po 
Ranb 
again  a 

To5tal 
utes  0.3 
Repla 
280 
300 

Breal 
Modul 

minutes  more,  beam  balanced  at  14 
The  pressure-screw  was  then  run 
.1  beam  balanced  again  at  5  pounds, 
ther  reading  of  set  taken. 
Inches.             Inch. 

0.20i8                 

im  sinks  slo\ 
0.0092 

0.0821 

8,039,339 
7,356,258 
6,594,770 
6,167,163 

v\y. 

5,638,814 

rose  again, 
ttinutes  balai 
minutes  bala 
minutes  bala 
ack  pressure 
:  5  pounds. 

ainutes  beam 
minutes  beai 
our  and  36 
unds. 
ack  pressure 
i.  5  pounds. 

decrease  ofi 
084  —  0.2^45 
ced  load  of  : 
0.4849 
0.5332 
Broke  on  a 
.ing  load,  3cx 

us  of  ruptur< 

iced  at  10  po 
need  at  \t  p( 
need  at  23  pc 
-screw  till  be 

0.2902 
rose  again, 
n  balanced  a 
minutes  bea 

-screw  till  be 

0.2845 
et  in  2  hours 
=  0.0239  incl 
280  pounds. 

unds. 
mnds. 
unds. 
am  balanced 

5,472,481 
4,899,597 
4,320,565 
3,77^245 
3,377,873 

1  14  pounds, 
m  balanced 

am  balanced 

and  20  min- 
i. 

0.1798 
0.2145 
0.2503 
0.3021 
0.3367 
0.3762 
0.4147 
0-4597 

;am  was  obse 
of  set  was  tal 

earn  rose  ag 
beam  balan< 
minutes. 

2,697,980 



832,406 

0.3084 
rved  to  rise, 
cen  in  2  min' 
0.3022 
ain,  pushed 
:ed  at  10  pou 

and  another 
ites. 

I 

pplying  strain. 
•>  pounds. 

*,  R  —  —  T"JO   ~  10,288. 

forward  the 
nds. 

No.   48.— Material:    Alloy.— Original    mixture:     12.5  Cu,  87.5  Sn.- Dimensions :    Length 
between  supports,  22";    Breadth,  0.985";  Depth,  0.990". 


.      10 

o  0025 

Scale  beam  rose. 

20 

0.0050 

In  2  minutes  balanced  at  20  po 

unds. 

£ 

80 

0.0141 
0.0230 
0.0752 
Bes 

m  sinks  siov 

7,901,458 
7,249,195 
6,330,144 
rly. 

In  4  minutes  balanced  at  29  pounds. 
In  15  minutes  balanced  at  ;u  pounds. 
Ran  back  pressure-screw  till  beam  balanced 
again  at  5  pounds. 

IOO 

5 

0.0508 

0.0120 

5,482,803 

5     I       0.6555 
Beam  rose  again,  balanced  at 

|     
12  pounds  in 

120 

0.0760 



4,397,784       5  minutes. 

140 

0.0969 

4,024,116 

5            0.6508 

160 

0.1262 

...'.'.. 

Total  decrease  of  set  in  20  minutes,  0.6742— 

1  80 

0.1592 

.'...' 

0.6508  =  0.0234  inch. 

200 

0.2044 

\[ 

2,725,307 

Beam  rose  again,  but  test  was  continued 

5 

0.1238 

without  further  waiting. 

200 

(X2268 

260          o  8704 

220 

o  2016 

280           o  0018 

240 
260 

•  y  " 
0.4078 

O    ^2IO 



1,639,194 

300           1.0760         Beam  sank  rapidly. 
300       Repeated.     Bar  broke  iust  as  beam 

270 

x 

o.  5703 

rose. 

280 

9'    x 

0.6458 



1,207,609 

Breaking  load,  300  pounds. 

2OO 

0.7185 

vyi 

300 

0.8025 

1,041,220 

Modulus  of  rupture,  R  =  ~TJ^  = 

=  10,  254. 

5 

0.6742 



500  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

to  be  determined.  The  bars  tested  as  shown  were  not  per- 
fect in  structure,  and  do  not  exhibit  any  considerable  strength ; 
they  consist  principally  of  tin  (82.5  and  87.5  per  cent.)  and 
are  valueless  for  the  ordinary  work  of  the  constructor,  although 
useful  "  white  metals."  It  is  seen  that  the  resistance  of  both 
bars  was,  at  times,  overcome  by  the  load,  but,  on  balancing 
the  weigh-beam,  the  bar  each  time  gradually  re-acquired  a 
power  of  raising  the  load  which  had  deformed  it,  and  straight- 
ened itself  sufficiently  to  raise  the  beam  against  the  upper 
"  chock."  A  decrease  of  set  took  place  of  0.02  inch — in  the 
first  beam  in  two  hours  and  twenty  minutes,  and  in  the 
second  in  twenty  minutes.  In  two  minutes,  recovery  occurred 
to  such  an  extent  that  the  bar  exerted  an  effort  of  20  pounds 
tending  to  straighten  itself,  and  in  15  minutes  of  34  pounds. 
The  phenomenon  is  one  which  will  demand  careful  investi- 
gation. 

283.  The  Effect  of  Unintermitted  and  Heavy  Stress  on 
Resistance  is  well  exhibited  on  the  two  sets  of  strain-dia- 
grams* here  reproduced  from  Part  II.  of  this  work.  The 
first  series  of  tests  exhibited  decrease  of  resistance  with  time 

No.  655  was  a  bar  of  Queensland  tin,  presented  to  the 
Author  by  the  Commissioner  of  that  country  at  the  Centen- 
nial Exhibition,  and  which  was  found  to  be  remarkably  pure. 
A  load  of  loo  pounds  gave  a  deflection  of  0.2109  inch,  and 
produced  a  set  of  0.1753  inch.  The  same  load  restored  de- 
flected the  bar  0.241 5  inch,  which  deflection  being  retained, 
the  effort  to  regain  the  original  shape  decreased  in  one  min- 
ute from  100  to  70  pounds,  in  3  minutes  to  62,  and  in  8  min- 
utes to  56  pounds.  The  original  load  of  100  pounds  then 
brought  the  deflection  to  0.3033  inch,  nearly  50  per  cent, 
more  than  at  first. 

A  bar,  No.  599,  of  copper-zinc  alloy,  similarly  tested, 
deflected  0.5209  inch  under  1,233  pounds,  and  took  a  set  of 
0.2736  inch  after  being  held  at  that  deflection  15  minutes, 
the  effort  falling  meantime  to  1,137  pounds.  Restoring  the 
load  of  1,137  pounds,  the  deflection  became  0.5131  inch,  and 
the  original  load  of  1,233  pounds  brought  it  to  0.5456  inch. 

*  Trans.  American  Society  of  Civil  Engineers,  1877. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      5OI 

The  bar  was  now  held  at  this  deflection  and  the  set  gradually 
took  place,  the  effort  falling  in  15  minutes  to  1,132  pounds 
(4  per  cent,  more  than  at  the  first  observation),  in  22  minutes 
to  1,093,  in  46  minutes  to  1,063,  in  63  minutes  to  1,043,  m 
gi}4  minutes  to  1,003,  an<^  m  IJ8  minutes  to  911  pounds,  at 
which  last  strain  the  bar  broke  3  minutes  later,  the  deflection 
remaining  unchanged  up  to  the  instant  of  fracture.  This 
remarkable  case  has  already  been  referred  to  in  an  earlier 
article,  when  treating  of  the  effect  of  time  in  producing  varia- 
tion of  resistance  and  of  the  elastic  limit. 

Nos.  561,  copper-tin,  and  612,  copper-zinc,  were  composi- 
tions which  behaved  quite  similarly  to  the  iron  bar  at  its 
first  trial,  the  set  apparently  becoming  nearly  complete, 
in  the  first  after  i  hour,  and  in  the  second  after  3  or  4 
hours. 

In  all  of  these  metals,  the  set  and  the  loss  of  effort  to 
resume  the  original  form  were  phenomena  requiring  time  for 
their  progress,  and  in  all,  except  in  the  case  of  No.  599 — 
which  was  loaded  heavily — the  change  gradually  became  less 
and  less  rapid,  tending  constantly  toward  a  maximum. 

So  far  as  the  observation  of  the  Author  has  yet  extended, 
the  latter  is  always  the  case  under  light  loads.  As  heavier 
loads  are  added,  and  the  maximum  resistance  of  the  material 
is  approached,  the  change  continues  to  progress  longer,  and, 
as  in  the  case  of  the  brass  above  described,  it  may  progress 
so  far  as  to  produce  rupture,  when  the  load  becomes  heavy, 
up  to  a  limit,  which  closely  approaches  maximum  tenacity  in 
the  "  iron  class."  The  brass  broke  under  a  stress  25  per  cent, 
less  than  it  had  actually  sustained  previously. 

The  records  are  herewith  presented,  and  the  curves  repre- 
senting them  shown  in  the  figures  which  follow. 


502    MA  TERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

TABLE   XCIV. 

DECREASE   OF   RESISTANCE  AND   INCREASE   OF   SET   OF   METALS,  WITH   TIME. 
Bars  i  inch  square ;  22  inches  between  supports. 


TIME. 

LOAD. 

LOSS  OF  LOAD. 

DEFLECTION. 

SET. 

TIME. 

LOAD. 

LOSS  OF  LOAD. 

DEFLECTION. 

SET. 

No.  64£ 

WROUGV 

T  IRON. 

First  Trial. 

, 

Min. 

Pounds. 

Pounds. 

Inches. 

Inch. 

Min. 

Pounds. 

Pounds. 

Inches. 

Inch. 



1,003 

0.0995 

3 

0.1091 

w 

3 

0.0049 

1,603 

0.287 

..... 

1,003 

..  '. 

O.IOOI 

I 

'82 

0.287 

25 

999 

4 

O.IOOI 

2 

1,493 

no 

0.287 

IOO 

12 

O.  IOOI 



3 

1,483 

1  20 

0.287 

275 

OS/ 

16 

O.  IOOI 

23 

1,463 

140 

0.287 

320 

987 

16 

O.IOOI 

53 

1,461 

142 

0.287 

320 

3 



o  007 

133 

T,459 

144 

0.287 

322 

987 

0.9910 

193 

i,457 

146 

0.287 

322 

1,003 

o.  1003 



363 

146 

0.287 

2,720 

...       i      2  .  6400 



363 

3 

0.148 

1,457 

0.2863 

Second  Trial. 

,^  ji 
i  603 

o.  3016 

•Liuuo 
2,720 

2.6400 

.....          1,003 

2    2548  | 

96.5 

993 

240 

0.5456 

No.  561.  —  27.5  PARTS  COPPER,  72.5  PARTS  TIN. 

118 

9" 

322 

121 

911 

326 

1    Broke 

..... 

160 

0.0696       



5 



0.0145 

No.  6l2.  —  47.5  PARTS  COPPER,  52.5  PARTS  ZINC 

160 

0.072 

I 

154 

"6 

0.072 



8co 

0.3332 

3 

150 

10 

0.072 

3 

0.1478 

2,640 

104 

56 

0.072 



808 

0.3366 

4,140 

IOO 

60 

0.072           

5 

790 

10 

0.3366 

5 

.  .  . 

!     0.04 

25 

778 

22 

0.3366 

-•••' 

IOO 

160 
320 

0.0763  ;    

0.0970  ;       
0.2200  ,    Broke 

120 
480 
1,320 

766 
756 
75* 

34 
44 
49 

0.3366 
0.3366 
0.3366 

No.  599.—  10  PARTS  COPPER,  90  PARTS  ZINC. 

75i 

::: 

0.3364 

o.  1688 

800 

0.3490 

,233 

0.5209 





1,100 

Broke 

15 

,T37 

0.5209 

3 

o  2736 

No.  655.  —  QUEENSLAND  TIN. 

,137 

0.5131 

.... 

,233 

0.3456 

IOO 

0.2109 

IS 

,133 

IOD 

0.5456 

3 

0.1753 

28 

,093 

140 

0-5456 

IOO 

0.2415 

4° 
46 
63 

,070 
,063 
,°43 

I63 
170 

I90 

o-5455 
0.5456 
0.5456 

:::: 

i 

7° 
62 

56 

30 

44 

0.2415 
0.2415 
0.2415 



77-5 

,023 

210 

0.5456 

IOO 

1,003 

230 

OT-O 
0.5456 



150 

o.  3^33        
Bent  rapidly. 

284.  The  Observed  Increase  of  Deflection  Under  Static 
Load. — In  the  preceding  article  the  writer  presented  results 
of  an  investigation  made  to  determine  the  time  required  to 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      503 

produce  "  set  "  in  metals  belonging  to  the  two  typical  classes, 
which  exhibit,  the  one  exaltation,  and  the  other  a  depression 
of  the  elastic  limit  under  strain. 

The  experiments  there  described  were  made  by  means  of 


FIG.  31. — DECREASE  OF  RESISTANCE  WITH  TIME. 

Rate  of  set  of  Bars  i   inch  square  22  inches  between   supports. 


a  testing-machine,  in  which  the  test-piece  could  be  securely 
held  at  a  given  degree  of  distortion,  and  its  effort  to  recover 
its  form  measured  at  intervals,  until  the  progressive  loss  of 
effort  could  no  longer  be  detected,  and  until  it  was  thus  in- 
dicated that  set  had  become  complete. 

The  deductions  were : 

That  in  metals  of  all  classes  under  light  loads  this  de- 


5O4   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

crease  of  effort  and  rate  of  set  become  less  and  less  notice- 
able until,  after  some  time,  no  further  change  can  be 
observed,  and  the  set  is  permanent. 

That  in  metals  of  the  "  tin  class,"  or  those  which  had 
'been  found  to  exhibit  a  depression  of  the  elastic  limit  with 
intermitted  strain,  under  a  heavy  load,  i.  e.,  a  load  consider- 
ably exceeding  the  proof  strain,  the  loss  of  effort  continued, 
until,  before  the  set  had  become  complete,  the  test-piece 
yielded  entirely. 

And  that  in  the  metals  of  the  "  iron  class,"  or  those 
exhibiting  an  elevation  of  elastic  limit  by  strain,  the  set  be- 
came a  maximum  and  permanent,  and  the  test-piece  remained 
unbroken,  no  matter  how  near  the  maximum  load  the  strain 
may  have  been. 

The  experiments  here  described  were  conducted  with  the 
same  object  as  those  above  referred  to.  In  these  experi- 
ments, however,  the  load,  instead  of  the  distortion,  was  made 
constant,  and  deflection  was  allowed  to  progress,  its  rate 
being  observed,  until  the  test-piece  either  broke  under  the 
load  or  rapidly  yielded,  or  until  a  permanent  set  was  pro- 
duced. The  results  of  these  experiments  are  in  striking 
accordance  with  those  conducted  in  the  manner  previously 
described.  They  exhibit  the  fact  of  a  gradually-changing 
rate  of  set  for  the  several  cases  of  light  or  heavy  loads,  and 
illustrate  the  striking  and  important  distinctions  between  the 
two  classes  of  metals  even  more  plainly  than  the  preceding. 
The  accompanying  record  and  the  strain-diagrams,  which  are 
its  graphical  representation,  will  assist  the  reader  in  compre- 
hending the  method  of  research  and  its  results.  All  test-pieces 
were  of  one  inch  square  section,  and  loaded  at  the  middle. 
The  bearings  were  22  inches  apart. 

No.  65 1  was  of  wrought  iron  from  the  same  bar  with  No. 
648.*  This  specimen  subsequently  gave  way  under  a  load  of 
2,587  pounds.  Its  rate  of  set  was  determined  at  about  60  per 
cent,  of  its  ultimate  resistance,  or  at  1,600  pounds.  Its  de- 
flection, starting  at,  0.489  inch,  increased  in  the  first  minute, 
0.1047;  in  the  second  minute,  0.026;  in  the  third  minute, 
*  Trans.  Am.  Soc.,  C.  E.,  vol.  v.,  page  208. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      505 

0.0125;  in  the  fourth  minute,  0.0088;  in  the  fifth  minute, 
0.0063;  and  in  the  sixth  minute,  0.0031  inch;  the  total  de- 
flections being  0.5937, 0.6197, 0.6322,  0.641,0.6473,  and  0.6504, 
inch.  In  the  succeeding  10  minutes  the  deflection  only 
increased  0.0094  inch,  or  to  0.6598  inch,  and  remained  at  that 
point  without  increasing  so  much  as  o.oooi  inch,  although  the 
load  was  allowed  to  remain  344  minutes  untouched.  The  bar 
had  evidently  taken  a  permanent  set,  and  it  seems  to  the 
writer  probable  that  it  would  have  remained  at  that  deflection 
indefinitely,  and  have  been  perfectly  free  from  liability  to 
fracture  for  any  length  of  time. 

This  bar  finally  yielded  completely,  under  a  load  of  2,589 
pounds,  deflecting  4.67  inches. 

No.  479  was  a  bronze  bar  containing  3^  per  cent,  of  tin. 
Its  behavior  may  be  taken  as  typical  of  that  of  the  whole 
"  tin  class  "  of  metals,  as  the  preceding  illustrates  the  behavior 
of  the  "  iron  class  "  under  heavy  loads.  It  was  subjected  to 
two  trials,  the  one  under  a  load  of  700  and  the  other  of  1,000 
pounds,  and  broke  under  the  latter  load,  after  having  sus- 
tained it  \y±  hours.  The  behavior  of  this  bar  will  be  con- 
sidered especially  interesting,  if  its  record  and  strain-diagram 
are  compared  with  those  of  No.  599,  previously  given,  which 
latter  specimen  broke  after  121  minutes,  when  held  at  a  con- 
stant deflection  of  0.5456  inch  ;  its  resistance  gradually  falling 
from  an  initial  amount  of  1,233  pounds,  to  911  pounds  at  the 
instant  before  breaking. 

This  bar,  No.  479,  was  loaded  with  700  pounds  "  dead 
weight,"  and  at  once  deflected  0.441  inch.  The  deflection 
increased  0.118  inch  in  the  first  five  minutes,  0.024  in  the 
second  five  minutes,  0.018  in  the  second  ten  minutes,  0.17  in 
the  fourth,  0.012  in  the  fifth,  and  0.008  inch  in  the  sixth  ten 
minute  period,  the  total  set  increasing  from  0.441  to  0.65 
inch.  The  record  and  the  strain-diagram  show  tha<-  at  the 
termination  of  this  trial  the  deflection  was  regularly  increas- 
ing. The  load  was  then  removed  and  the  set  was  found  to 
be  0.524  inch,  the  bar  springing  back  0.126  inch  on  removal 
of  the  weight. 

The  bar  was  again  loaded  with  1,000  pounds.     The  first 


506  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

deflection  which  could  be  measured  was  3.118  inches  and  the 
increase  at  first  followed  the  parabolic  law  noted  in  the  pre- 
ceding cases,  but  quickly  became  accelerated ;  this  sudden 
change  of  law  is  best  seen  on  the  strain-diagram.  The 
new  rate  of  increase  continued  until  fracture  actually  oc- 
curred, at  the  end  of  ij^  hours,  and  at  a  deflection  of  4.506 
inches. 

This  bar  was  of  very  different  composition  from  No.  599 ; 
it  is  a  member  of  the  "  tin  class,"  however,  and  it  is  seen,  by 
examining  their  records  and  strain-diagrams,  that  these 
specimens,  tested  under  radically  different  conditions,  both 
illustrate  the  peculiar  characteristics  of  the  class,  by  similarly 
exhibiting  its  treacherous  nature. 

No.  504  was  a  bar  of  tin  containing  about  0.6  per  cent,  of 
copper — the  opposite  end  of  the  scale — and  exhibited  pre- 
cisely similar  behavior,  taking  a  set  of  0.323  inch  under  no 
pounds  and  steadily  giving  way  and  deflecting  uninterruptedly 
until  the  trial  ended  at  the  end  of  1,270  minutes,  over  2t 
hours.  This  bar,  subsequently,  was,  by  a  maximum  stress  of 
130  pounds,  rapidly  broken  down  to  a  deflection  of  8.11 
inches. 

No.  501  presents  the  finest  illustration  of  this  phenomenon 
yet  met  with  by  the  Author.  The  test  extended  over  nearly 
£/2  days  under  observation,  and  the  bar  left  for  the  night  was 
found  next  morning  broken.  The  time  of  fracture  is  there- 
fore unknown,  as  is  the  ultimate  deflection.  The  record 
is,  however,  sufficient  to  determine  the  law,  and  the  strain- 
diagram  is  seen  to  be  similar  to  that  of  the  second  test  of  No. 
479,  exhibiting  the  same  tendency  to  the  parabolic  shape  and 
the  same  change  of  law  and  reversal  of  curvature  preceding 
final  rupture,  and  illustrates,  even  more  strikingly,  the  fact 
that  this  class  of  metals  is  not  safe  against  final  rupture,  even 
though  the  load  may  have  been  borne  a  considerable  time, 
and  have  apparently  been  shown,  by  actual  test,  to  be  capable 
of  sustaining  it.  A  strain-diagram  of  each  of  the  latter  two 
bars  is  exhibited  on  a  reduced  scale  to  present  to  the  eye 
more  strikingly  this  important  characteristic. 

A  comparison  of  the  records  and  the  strain-diagrams  with 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS,       5O/ 

those  of  the  preceding  article,  in  illustration  of  the  behavior 
of  the  two  classes  of  metals  under  constant  deflection,  is  most 


FIG.  32. — INCREASE  OF  DEFLECTION  WITH  TIME. 

Rate  of  Set  of  Bars  i  Inch  Square  22  Inches  Between  Supports. 


instructive.  It  will  still  be  necessary  to  make  many  experi- 
ments to  determine  under  what  fraction  of  their  ultimate 
resistance  to  rapidly  applied  and  removed  loads,  the  members 
of  the  "  tin  class" — the  viscous  metals — will  be  safe  under 
static  permanent  loads.  The  records  in  Table  LXXXIII., 
Art.  267,  present  many  illustrations  of  the  phenomenon  here 
considered. 


508    MA  TERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

TABLE  XCV. 

INCREASE    OF   DEFLECTION   WITH   TIME. 
Bars,  i  inch  square  ;  22  inches  between  supports.     Load  applied  at  the  middle. 


z 

o 

INCREASE. 

§ 

INCREASE. 

H 

5 

TIME. 

3 

TIME. 

3 

H 

Q 

Difference. 

Total. 

i 

Difference. 

Total. 

No.  651.  —  WROUGHT  IRON. 

Min. 

Inches. 

Inches. 

Inches. 

30 

0.618 

0.017 

0.177 

Load,  i,  600  pounds. 

40 

0.630 

O.OI2 

0.189 

Min. 
o 

Inches. 

0.4890 

Inches. 

Inches. 

5° 
60 

0.642 
0.650 

0.012 

0.008 

0.201 
0.209 

i 

0.5937 

0.1047 

0.1047 

Set 

0.524 





2 

0.6197 

0.0260 

0.1307 

3 

0.6322 

0.0125 

0.1432 

Second  Trial.  —  Load,  1,000  pounds. 

4 

0.6410 

0.0088 

o.  1520 

0.6473 

0.0063 

0.1583 

0 

3.118 



6 

0.6534 

0.0031 

0.1614 

5 

3.540 

0.422 

0.422 

16 

0.6598 

0.0094 

o.  1708 

3.660 

0.120 

0.542 

544            0.6598              o.oooo 
Maximum  load,  2,589  pounds; 
deflection,  4.67  inches.                  » 

0.1708 
maximum 

45 
Broke 

4.102 
7-634 
bar  under  i, 

0.442 
3.522 

ooo  pounds. 

0.984 
4.506 

No.  504.—  0.557  PARTS  COPPER,  99.443  PARTS  TIN. 

No.   501.—  9.7  PARTS  COPPER,  90.3  PARTS  TIN. 

o 

Load,  no  pounds. 
323 

o 

Load,  1  60  pounds. 

.  294 

5 

.406 

0.083 

0.083 

10 

.319 

0.025 

0.025 

845 

•945 

1-539 

1.622 

70 

.463 

0.144 

o.  169 

865 

.005 

0.059 

1.681 

130 

•  530 

0.067 

0.236 

895 

.138 

o.i34 

1.815 

310 

.691 

0.161 

0.397 

1,025 

.248 

o.  no 

1-925 

400 

.766 

0.075 

0.472 

1,110 

.378 

0.130 

2.055 

460 

.811 

0.045 

0.517 

faaxin 
deflectio 

2.626 
lum    load,   i 
n,  8.  ii  inche 

0.248 
30    pounds; 
5. 

2.303 
maximum 

,360 

,475 

,565 

-534 
.697 
.782 

0.723 
0.163 
0.085 

1.240 

1.403 

1.488 

'730 

•938 

0.156 

1.644 

,880 

3.136 

0.198 

1.842 

No.  479.  —  96.27  PARTS  COFFER,  3.73  PARTS  TIN. 

,780 
,940 

3.798 
4.274 

0.662 
0.476 

2.504 
2.980 

0 

Load, 
0.441 

foo  ponnds. 

3,000 

3,295 

Bar  1< 

4-349 
5-097 
;ft  under  st 

0.075 
•ain  at  nierh 

3.055 
3.803 
t  and  found 

5 

0-559 

0.118* 

0.118 

broken  in  the  morning. 

IO 

0.583 

0.024 

o.  142 

20 

0.601 

0.018 

0.160 

285.  Depression  of  Elastic  Limits. — The  effects  of  inter- 
mitted stress  and  of  interrupted  strain  are  of  peculiar  interest 
and  importance  with  the  non-ferrous  metals  and  the  alloys. 
So  far  as  they  have  been  observed  by  the  Author,  they  are 
often  precisely  the  opposite  of  those  noted  in  experiments  on 
merchant  iron  and  commercial  grades  of  steel.  They  are 
well  illustrated  in  Fig.  33,  which  is  here  reproduced  from 
Part  II. 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLOYS.      509 


These  strain-diagrams  are  obtained  by  transverse  test, 
from  bars  of  common  iron,  Nos.  648,  649,  650,  651,  and  from 
two  specimens  of  bronzes,  Nos.  596,  599,  all  of  the  same  size, 


9-9  Btl 


I  inch  (2.54  cm.)  square  and  22  inches  (55.9  cm.)  between  sup- 
ports. 

The  first  strain  diagram  to  be  studied  is  that  of  a  bar  of 
the  most  ductile  metal  (No.  599,  copper,  10;  zinc,  90).  It 
exhibits  clearly  the  phenomenon  of  flow  with  a  depression  of 
the  elastic  limit  under  constant  load. 


5IO  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

'  This  bar  was  left  deflected  under  a  load  of  163  pounds 
(74  kgs.).  It  gradually  lost  its  power  of  restoration  until  it 
only  exhibited  an  effort  of  143  pounds  (65  kgs.).  The  curve 
exhibits  the  relation  of  deflection  to  deflecting  force.  The 
resistance  gradually  increased  as  deflection  progressed  until 
the  load — 403  pounds  (183  kgs.) — produced  a  deflection  of 
0.09  inch  (0.23  cm.).  The  bar  was  again  left,  and,  under  a 
fixed  deflection,  again  lost  resisting  power,  and  the  effort  to 
straighten  itself  fell  to  333  pounds  (151  kgs.). 

Finally,  the  bar  offered  its  maximum  resistance  of  1,233 
pounds  (560  kgs.)  under  a  deflection  of  0.545  inches  (1.3  cm.), 
and  was  then  held  in  its  flexed  position.  Gradually  its  effort 
to  restore  itself  grew  less  and  less,  until,  when  it  had  fallen  to 
911  pounds  (414  kgs.),  the  bar  suddenly  snapped  and  the  two 
halves  fell  to  the  floor. 

No.  596  (copper  25,  zinc  75)  similarly  exhibited  a  depres- 
sion of  the  elastic  limit  by  strain,  but,  vastly  harder,  more 
elastic  and  brittle,  it  broke  under  663  pounds  (301  kgs.)  and 
at  a  deflection  of  o.i  136  inch  (0.3  cm.),  before  apparently  pass- 
ing the  point  termed  the  primitive  or  apparent  limit  of  elastic- 
ity by  the  Author,  i.e.,  that  point  at  which  the  sets  become 
nearly  proportional  to  the  strains,  and  at  which  the  line  of  the 
strain-diagram  turns  sharply  away  from  the  vertical. 

The  strain-diagram  No.  648,  common  iron,  is  that  of  the 
type  of  that  class  in  which  the  elevation  of  the  elastic  limit 
has  been  detected  by  the  Author. 

The  bar  was  like  the  preceding,  of  I  inch  (2. 54  cm.) 
square  section  and  22  inches  (55.88  cm.)  in  length  between 
bearings.  It  reached  its  elastic  limit  at  1,450  pounds 
(659  kgs.)  and  at  a  deflection  of  0.15  inch  (0.4  cm.).  Pass- 
ing this  point,  and  at  a  deflection  of  0.287  inch  (0.7  cm.),  the 
bar  was  held  at  a  constant  deflection,  under  a  load  of  1,600 
pounds  (727  kgs.).  Flow  occurring,  the  effort  to  regain  its 
original  shape  became  less  and  less,  until  in  six  hours  it  had 
fallen  to  1,457  pounds  (662  kgs.).  Continuing  the  test,  re- 
sistance and  deflection  increased  as  indicated  by  the  curve, 
instead  of  following  the  original  direction. 

Similar  increase  of  resisting  power  under  strain  is  seen  at 


CONDITIONS  AFFECTING  STRENGTH  OF  ALLO  VS.      5  1 1 

other  points  on  the  curve,  and  whenever  the  process  of  dis- 
tortion was  interrupted  long  enough  to  permit  flow  and  that 
re-arrangement  of  particles  which  has  been  described.  An 
hour  or  two  usually  gave  time  enough  to  bring  out  this  re- 
markable phenomenon. 

This  action  has  been  discovered  in  iron  and  steel,  and 
under  every  form  of  strain — tension,  torsion,  compression  and 
cross-breaking — and  it  would  seem  that  aside  from  accidental 
overstrain,  producing  incipient  rupture  or  loss  of  strength  due 
to  such  action  as  abrasion  or  corrosion,  length  of  life  of  iron 
structures  under  strain  was  in  itself,  apparently,  a  source  of 
increased  safety.  On  the  other  hand,  as  is  here  seen,  the  be- 
havior of  non-ferrous  metals  is  precisely  the  opposite,  and 
the  engineer  is  compelled  to  use  them  with  greater  caution 
and  to  base  his  calculations  upon  a  higher  factor  of  safety, 
a  conclusion  fully  corroborated  by  the  work  of  Wohler. 

Recurring  to  Fig.  33,  a  resemblance  is  to  be  noted  in 
the  behavior  of  both  classes  of  metals. 

The  bars  No.  649,  650  and  65 1  were  tested  by  rapidly  in- 
creased load  up  to  the  breaking  point,  allowing  no  time  for 
reading  of  sets. 

The  first  of  this  set  deflected  0.014  inch  (0.04  cm.)  under 
IOO  pounds  (45  kgs.),  0.052  under  500  pounds,  0.098  under 
1,000  pounds,  and  0.18  under  1,500  pounds.  At  1,600  pounds 
the  deflection  was  0.2854  inch,  and  the  bar  yielded  to  the 
stress,  and  the  deflection  became  0.363  in  2^  minutes.  Under 
1,640  pounds  the  deflection  increased  in  six  minutes  from 
0.383  to  0.440  inch,  and  a  maximum  resistance  was  recorded 
of  2,350  pounds  (1,070  kgs.),  and  a  deflection  of  5.577  inches 
(15  cm.).  This  bar  was  tested  in  a  similar  manner  to  the 
preceding,  and  in  the  same  machine. 

Numbers  650  and  651  were  tested  by  dead  loads — i.e., 
by  laying  upon  them  heavy  weights.  By  this  method  the 
deflection  could  increase  to  a  maximum  under  each  load,  in- 
stead of  being  kept  constant,  as  in  the  testing  machine.  No. 
650  was  rapidly  broken  without  allowing  time  for  completion 
of  set  or  any  considerable  exaltation  of  the  elastic  limit.  The 
plotted  curves  of  results  exhibited  well  the  striking  difference 


512  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

of  behavior  between  this  bar  and  651,  which  was  purposely 
given  time  for  set  and  for  exaltation  of  the  elastic  limit.  At 
1, 500  pounds  (682  kgs.)  each  had  deflected  nearly  the  same 
amount,  and  had  passed  the  elastic  limit,  as  usually  called. 
The  first,  however,  gave  way  completely  with  2,260.5  pounds 
(1,027  kgs.),  while  the  second,  after  several  times  exhibiting 
an  elevation  of  the  elastic  limit — as  at  1,500,  1,600,  1,700, 
1,900,  2,300,  2,400  and  at  2,500  pounds — finally  only  yielded 
entirely  at  2,589.  The  first  only  deflected  2^  inches  (7  cm.); 
the  second,  4.67  inches  (11.9  cm.);  although  when  the  latter 
was  loaded  with  about  the  weight  at  which  the  first  yielded,  it 
deflected  about  the  same  amount. 

The  last  bar  was  left  two  and  a  half  days  under  its  final 
load,  and  its  deflection  increased  from  4.275  inches  (109  cm.) 
to  4.67  (11.9  cm.),  when  the  weights  reached  the  supports  of 
the  frame  and  the  test  was  ended.  The  other  bar  sank 
rapidly  after  being  loaded  with  1,600  pounds  (726  kgs.). 

Both  classes  of  metals,  when  flexed,  were  shown  to  exhibit 
less  and  less  effort  to  restore  themselves  to  their  original 
form.  In  the  case  of  the  tin  class,  as  the  Author  has  called 
it,  this  continues  indefinitely.  With  the  iron  group  this  loss 
of  effort  gradually  becomes  less  and  less  and  reaches  a  limit 
at  which  the  bar  is  found  to  become  stronger  than  at  first. 
The  two  classes  are  thus  seen  to  be  affected  by  time  in 
precisely  the  same  manner  initially,  but  finally  in  exactly 
opposite  ways. 

286.  The  Effect  of  Variable  Stress  in  causing  variation 
of  the  normal  series  of  elastic  limits  observed  during  ordinary 
tests  is  well  shown  by  the  records  of  test  of  the  copper-zinc 
alloys.  The  following  are  extracts  from  the  memoranda 
taken  during  tests  made  for  the  U.  S.  Board  to  which  fre- 
quent references  are  made.  Similar  illustration  may  be 
found  among  the  records  of  tests,  both  of  bronzes  and  of 
brasses,  already  given. 

Bar  No.  8  (60.94  copper,  38.65  zinc)  bent  to  a  deflection  of 
3^2  inches  under  a  load  of  1,140  pounds.  The  apparent 
elastic  limit  was  reached  at  about  640  pounds.  At  400 
pounds  the  bar  was  left  under  stress  for  eighteen  hours,  at  the 


CONDITIONS  AFFECTING  STRENG  TH  OF  ALLO  YS.      5  1 3 

end  of  which  time  the  scale-beam  was  found  still  balanced, 
the  resistance  to  a  constant  deflection  being  unchanged.  At 
800  pounds  the  scale  beam  dropped  and  the  resistance  de- 
creased 1 8  pounds  in  one  hour. 

After  leaving  the  bar  under  a  stress  of  800  pounds  for  one 
hour,  taking  the  reading  of  a  set,  then  applying  a  stress  of 
840  pounds,  the  deflection  was  0.0185  inch  over  the  deflection 
produced  by  800  'pounds.  The  load  was  increased  to  880 
pounds,  and  the  deflection  increased  0.441  inch.  An  ad- 
ditional 20  pounds  then  increased  the  deflection  only  0.020 
inch,  and  another  20  pounds  only  0.0515  inch.  Successive 
additions  of  20  pounds  at  a  time  were  applied,  and  the  in- 
creased amounts  of  deflection  were  as  follows  :  0.22,  0.07,  0.20, 
0.09,  0.25,  o.  10,  0.25,  o.io  inch.  The  time  occupied  in  applying 
the  load  was  as  regular  as  possible,  about  30  seconds.  This 
irregularity  of  resistance  to  distortion  has  been  also  observed 
both  in  tensile  and  torsional  tests  of  pieces  obtained  from 
the  same  bar,  and  of  other  bars  of  nearly  similar  composi- 
tions. 

Bar  No.  10  (49.66  copper,  50.14  zinc)  broke  at  a  load  of  940 
pounds  after  a  deflection  of  1.257  inches.  The  weakness  was 
due  to  unfavorable  conditions  of  casting.  'The  fractured  sur- 
face showed  a  finely  porous  or  spongy  surface,  and  the  com- 
position was  not  homogeneous.  The  limit  of  elasticity 
was  passed  at  320  pounds.  At  200  pounds  the  scale  beam 
was  observed  to  sink  very  slowly. 

After  200  pounds  had  been  applied,  a  slight  crackling 
sound  like  the  "  cry  of  tin  "  was  heard  to  proceed  from  the 
bar,  which  continued  for  two  or  three  minutes,  while  the  de- 
flection was  held  constant  by  the  pressure-screw.  After  it 
had  ceased  to  be  distinctly  audible  it  could  be  heard  on  ap- 
plying the  ear  to  the  bar.  With  every  increase  of  load  the 
same  phenomenon  took  place  till  the  bar  broke. 

After  940  pounds  had  been  applied,  slight  cracks  were 
heard  and  the  scale-beam  dropped.  The  poise  was  pushed 
back  and  the  beam  balanced  at  580  pounds.  No  crack  could 
be  perceived  in  the  bar,  and  no  indication  of  fracture.  After 
reading  the  deflection  the  pressure  was  then  taken  off  the  bar 


MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

and  a  reading  of  set  taken.  The  pressure  was  again  gradually 
applied,  and  when  it  reached  500  pounds  the  bar  broke. 

The  sudden  decrease  of  resistance  from  940  to  580  pounds 
without  visible  appearance  of  breaking  cannot  be  explained. 
The  crackling  sound  emitted  by  the  bar  during  the  whole 
test  after  passing  a  load  of  200  pounds,  and  when  it  was  held 
at  a  constant  deflection  for  several  minutes,  is  evidence  of 
molecular  change,  probably  the  "  flow  of  metals  "  described 
by  Tresca. 

Bar  No.  11  (47.56  copper,  52.28  zinc)  behaved  much  like 
No.  10,  but  was  much  stronger,  breaking  at  1,360  pounds. 
The  elastic  limit  was  passed  at  450  pounds.  At  460  pounds 
the  scale-beam  sank  about  16  seconds  after  it  balanced. 
At  560  pounds  a  crackling  sound  was  heard  from  the  bar  like 
that  emitted  from  bar  No.  10,  which  continued  for  10  minutes, 
gradually  growing  fainter.  With  the  same  deflection,  the  re- 
sistance decreased  50  pounds  in  15  hours.  On  proceeding 
with  the  test  the  next  day,  the  crackling  sound  was  again 
given  out  by  the  bar,  and  continued  till  the  bar  broke  at 
1,360  pounds,  after  a  deflection  of  1.17  inches. 

Bar  No.  19  (10.30  copper,  88.88  zinc)  was  similar  in  charac- 
ter to  other  bars  containing  a  large  proportion  of  zinc,  but 
was  stronger,  sustaining  a  load  of  1,233  pounds  before  rupture. 
It  broke,  however,  at  911  pounds,  two  hours  after  it  had  sus- 
tained the  load  of  1,233  pounds.  The  total  deflection  before 
breaking  was  0.5456  inch.  The  record  of  this  test  is  given  in 
full  in  the  tables,  and  is  entirely  unlike  that  of  any  other  bar 
tested.  Three  "  time  tests"  were  made  at  163,403,  and  1,233 
pounds,  which  showed  the  common  phenomenon  of  decrease 
of  resistance  with  time.  In  the  last  case  the  resistance  de- 
creased from  1,233  to  i, 137 pounds  in  fifteen  minutes.  After 
taking  a  reading  of  the  set,  the  load  of  1,233  pounds  was  again 
applied  and  the  decrease  of  resistance  with  time  noted  at 
intervals  during  a  period  of  two  hours. 

The  decrease  of  resistance  was  at  first  rapid,  100  pounds 
in  the  first  fifteen  minutes,  and  then  much  slower.  In  the 
fifteen  minutes,  commencing  at  one  hour  and  three  minutes 
after  the  beginning  of  the  "  time  test,"  the  decrease  was  20 


Or  THfc- 

UNIVERSITY 

CONDITIONS  AFFECTING  STRENGTlF'#j? 

pounds ;  in  the  next  fourteen  minutes  the  decrease  was  again 
20  pounds.  In  the  five  minutes,  commencing  one  hour  and 
thirty-two  minutes  after  the  "  time  test,"  the  decrease  was  10 
pounds,  showing  an  increase  of  the  rate  of  decrease.  Another 
observation  was  twenty-two  minutes,  when  the  rate  was  found 
to  have  largely  increased,  the  decrease  of  resistance  in  these 
twenty-two  minutes  being  82  pounds.  In  three  minutes 
after  taking  the  last  reading,  when  it  balanced  at  911  pounds, 
the  bar  suddenly  broke  without  warning.  The  deflection  was 
unchanged  during  this  entire  "  time  test."  The  elastic  limit 
was  reached  at  about  900  pounds. 

287.  The  Effect  of  Repeated  Strain  is  greater  with  the 
non-ferrous  metals,  and  usually  with  the  alloys,  than  with  iron 
and  steel.  The  investigations  of  Wohler  and  Spangenberg 
were  made  principally  upon  the  latter  class  of  materials,  but 
were  also  made  to  cover  the  action  of  a  few  other  metals. 

Wohler's  law,  that  the  rupture  of  a  piece  may  be  pro- 
duced by  the  repeated  action  of  a  load  less  than  that  which, 
once  applied,  would  cause  fracture,  is  true,  probably,  of  all  the 
non-ferrous  metals,  and  this  effect  is  with  them  much  more 
serious  than  with  the  ferrous  metals.  Spangenberg  found 
that  gun  bronze  in  tension  would  endure  a  stress  of  22,000 
pounds  per  square  inch  (1,547  kgs.  per  sq.  cm.)  laid  on  and  at 
once  removed  4,200  times  before  rupture;  a  stress  of  16,500 
pounds  (1,160  kgs.)  6,300  times,  and  11,000  pounds  per  square 
inch  (773  kgs.  per  sq.  cm.),  5,547,600  times.  It  may  be  con- 
sidered safe  under  indefinitely  repeated  loads  falling  well 
under  one-half  its  tenacity  as  determined  by  ordinary  test. 
Phosphor  bronze,  forged,  bore  53,900  repetitions  of  the  small- 
est of  the  above  loads,  and  2,600,000  of  the  next  load,  but 
broke  under  1,621,000  repetitions  of  a  load  of  13,750  pounds 
per  square  inch  (967  kgs.  per  sq.  cm.).  The  cast  metal  sus- 
tained 408,350,  2,731,161  and  2,340,000  repetitions  of  the 
same  loads.  This  peculiar  behavior  is  not  explained  by  the 
experimenter. 

Further  experiment  in  this  direction  is  desirable.  Mean- 
time, the  engineer  will  probably  find  it  advisable  to  allow,  for 
intermittent  loads,  but  one-half  the  stresses  which  would  be 


5l6  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

permitted  for  single  applications  of  load,  and  one-quarter 
where  suddenly  applied,  while  the  factor  of  safety  should 
be  probably  not  less  than  one-half  greater  for  non-ferrous 
material  than  with  iron.  The  limits  of  stress  sometimes  pro- 
posed are  not  far  from  the  following,  which  may  be  compared 
with  the  values  already  given  for  factors  of  safety  and  ulti- 
mate strength. 


TABLE   XCVI. 

PERMISSIBLE   REPEATED    STRESSES    FOR    NON-FERROUS    METALS. 


. 

FACTOR  OF  SAFETY. 

MAXIMUM    STRESS. 

Dead  Load. 

Live  Load. 

T\         JI 

Load. 

Load. 

L«bs.    per 

Kgs.  per 

Lbs.  per 

Kgs.  per 

sq.  in. 

sq.  cm. 

sq.  in. 

sq.  cm. 

Copper,  cast  

4 

8 

">  OOO 

<7C2 

2  ^OO 

176 

4  '       forged     ... 

8 

15  ooo 

I  O<^ 

7  ^OO 

528 

'*       wire     

A 

8 

16  ooo 

I   12^ 

8  ooo 

56-* 

Gun-bronze,  cast  

4 

8 

10,000 

703 

5,000 

352 

Brass,  yellow,  cast  .  .  . 

4 

8 

5,000 

352 

2,500 

176 

rolled  . 

4 

8 

10,000 

703 

5,000 

352 

"         wire  .  . 

4 

8 

12,000 

845 

6,000 

423 

Lead,  rolled  

4 

3 

1,000 

70 

500 

35 

When  the  stresses  are  reversed,  as  in  connecting  rods,  the 
factor  of  safety  should  be  doubled  and  the  maximum  stresses 
reduced  at  least  one-half. 


CHAPTER   XIV. 

MECHANICAL  TREATMENT  OF  THE   METALS.* 

288.   Qualities  Affected  by  Mechanical  Treatment*— 

The  metals  used  by  the  engineer  in  construction,  as  they  are 
found  in  the  market,  and  often  when  they  have  been  given 
the  form  and  dimensions  desired  in  the  finished  piece,  are 
known  to  be  liable  to  exhibit  certain  defects  and  to  possess 
certain  peculiar  characteristics.  Some  of  these  defects  are 
removable  by  proper  mechanical  treatment,  and  some  of  the 
characteristic  qualities  may  be  modified  in  a  marked  manner 
by  special  methods  of  manipulation.  All  known  and  actually 
practised  methods  of  so  altering  the  character  of  the  metals 
used  by  the  engineer,  involve,  directly  or  indirectly,  the  ele- 
vation of  the  original  elastic  limit  of  the  material;  and  they 
usually  produce  a  change,  more  or  less  marked,  in  the 
ultimate  strength,  the  elasticity,  the  resilience— in  fact,  in 
all  the  physical  properties  of  the  metal. 

The  subject  of  the  mechanical  treatment  of  metals  has 
already  been  considered,  incidentally,  and  to  a  very  limited 
extent,  in  Part  II.  of  this  work.f  It  is  intended,  in  the  pres- 
ent chapter,  to  describe  successful  and  established  methods 
at  some  length,  when  they  have  not  already  been  so  described. 
The  effect  of  mechanical  treatment  is  due  to  that  change  of 
volume,  density,  and  condition  of  molecular  aggregation  which 
is  produced  by  any  action  causing  flow  while  under  stress, 
and,  especially,  while  under  compression.^:  This  action  is 
sometimes,  as  in  wire  drawing,  incidental  to  the  process  of 


*  Principally  from  an  article  contributed  to  the  Metallurgical  Review,  1877. 
f  Part  II.,  §§  48,  165,  178,  191,  pp.  71,  196*  262»  328 
\  Part  II.,  Chapter  X. 


5l8  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

manufacture,  and  sometimes,  as  in  the  Whitworth  or  Jones 
systems  of  compressing  ingot  metal,  and  as  in  the  cold-rolling 
process,  an  independent  operation. 

Mechanical  treatment  does  not  directly  modify  the  chem- 
ical composition  of  the  metal,  and  is,  therefore,  incapable  of 
changing,  either  for  better  or  worse,  the  nature  of  the  mate- 
rial, so  far  as  it  is  determined  by  the  chemical  constitution. 
So  important,  however,  are  the  modifications  which  can  be 
effected  by  mechanical  treatment,  and  so  extensively  are  they 
likely  to  be  applied  in  the  arts,  that  a  more  extended  and  a 
more  precise  analysis  than  can  be  here  given  would  be  re- 
quired to  do  full  justice  to  the  subject. 

All  defects  removable  by  mechanical  treatment  may  be 
properly  classed  as  defects  involving  want  of  homogeneous- 
ness.  Metals  maybe  homogeneous  in  two  ways :  (i.)  They 
may  be  homogeneous  in  structure — i.e.,  they  may  be  free  from 
such  defects  as  blow-holes,  which  are  generally  numerous  in 
cast  metals,  and  from  the  cinder  streaks  which  produce  the 
fibre  in  rolled  and  forged  iron ;  the  molecules  of  the  several 
constituents  of  which  they  are  composed  are  then  uniformly 
distributed  ;  (2.)  The  metal  may  be  homogeneous  as  to  strain 
— i.e.,  it  may  be  free  from  such  stresses  as  are  known  often 
to  exist  in  badly  designed  castings  of  brittle  materials  like 
hard  cast  iron,  speculum  metal,  and  in  glass. 

Defective  homogeneousness  of  structure  maybe  removed, 
more  or  less  completely,  at  any  temperature  below  that  of 
fusion,  by  methods  specially  adapted  to  use  at  the  given  tem- 
perature. 

Blow-holes  are  probably  due  to  the  presence  of  air  and  of 
other  gases,  either  absorbed  from  the  atmosphere,  as  illus- 
trated in  the  "  spitting  "  of  silver,  or  developed  by  chemical 
actions  occurring  within  the  mass  of  metal  while  in  a  state  of 
fusion.  This  gas  can  be  condensed,  excluded  or  expelled, 
either  by  the  mechanical  act  of  compression,  or  by  the  use  of 
some  material  in  the  form  of  a  flux,  which  shall  either  prevent 
the  development  or  the  absorption  of  the  gas,  or  which  shall 
unite  with  it,  forming  a  compound  which  can  be  separated 
by  the  usual  process  of  skimming  the  molten  metal  in  the 


MECHANICAL  TREATMENT  OF  THE  METALS.          519 

melting  pot,  or  which  shall,  if  retained  in  the  mass,  be  less 
injurious  than  the  free  gas. 

The  latter  process  is  illustrated  in  the  use  of  silicon  and 
of  manganese  to  confer  soundness  upon  the  cast  ingots  in  the 
Bessemer  and  other  processes  of  steel  making,  and  by  the 
use  of  phosphorus  in  insuring  soundness  in  the  better  class 
of  copper-tin  and  of  copper-zinc  alloys,  which  metals  are  very 
liable  to  be  made  seriously  defective  by  the  absorption  of 
oxygen  and  the  formation  of  oxide.  The  bronzes  especially, 
when  rich  in  copper,  are  exceedingly  liable  to  this  kind  of 
defect,  and  the  immense  increase  in  the  tenacity,  ductility, 
and  other  valuable  qualities  of  such  alloys,  which  may  be  ob- 
tained by  securing  perfect  soundness  by  such  removal  of  the 
cause  of  their  unsoundness,  has  only  recently  been  made  gen- 
erally known. 

The  density  of  yellow  copper  (65  copper  to  35  tin)  is  in- 
creased by  working  it  mechanically.  Mechanical  action, 
chilling,  etc.,  usually  produce  no  perceptible  change  in  the 
volume  of  pinchbeck,  an  alloy  of  91  copper  to  9  zinc,  or  in 
aluminium  bronze,  both  of  which  are  remarkable  for  the  ease 
with  which  they  may  be  wrought. 

289.  The  Whitworth  Process. — The  mechanical  treat- 
ment of  metal  at  the  point  of  fusion,  for  the  purpose  of 
securing  homogeneity  of  structure,  is  illustrated  by  the  Whit- 
worth  process  of  making  compressed  steel. 

In  all  the  usually  practised  methods  of  making  steel,  the 
metal  is  cast  in  ingots,  which  are  subsequently  hammered  or 
rolled  into  any  desired  shape.  The  steel  is  sometimes  poured 
into  moulds  and  given  working  shapes  like  cast  iron;  the 
resulting  shapes  are  known  in  the  market  as  "  steel  castings." 

These  ingots  or  castings  are  very  liable  to  contain  blow- 
holes or  air  cells,  which  are  produced  by  the  retention,  while 
solidifying,  of  occluded  air  and  bubbles%f  disengaged  carbon 
monoxide  originating  in  the  oxidation  of  a  portion  of  the 
carbon  previously  united  with  the  metal.  The  lower  the  per- 
centage of  carbon  present,  the  greater  the  injury  produced  in 
this  manner.  The  use  of  manganese  is  resorted  to  for  the 
purpose  of  preventing  this  "  piping ;  "  but  as  it  is  used  in  the 


52O    MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

form  of  a  carbide,  it  is  usually  found  difficult  to  use  a  sufficient 
quantity  of  manganese  in  the  "  milder"  steels  without,  at  the 
same  time,  introducing  too  much  carbon.  Silicon,  also,  has 
been  found  to  possess  the  same  property  in  an  even  higher 
degree  than  manganese.  One  or  two  one-hundredths  of  one 
per  cent,  has  been  said  to  reduce  liability  to  such  porosity 
very  greatly.  At  Terrenoire,  France,  the  double  silicide  of 
iron  and  manganese,  instead  of  spiegeleisen,  is  added  to  the 
molten  metal  as  a  carburizer. 

In  large  castings  and  ingots,  also,  the  internal  strains,  in- 
duced by  the  contraction  of  the  inner  portions  after  the 
external  part  of  the  mass  has  solidified,  produce  serious 
weakness,  and  often  crack  the  whole  body  of  metal  to  such 
an  extent  as  to  entirely  destroy  its  value.  This  is  peculiarly 
liable  to  occur  in  hard  steels.  Such  steels  are  entirely  unfitted 
for  the  use  of  the  engineer  in  construction  ;  and  such  metal 
is  only  used  for  tools.  The  "  low  "  steels,  on  the  contrary, 
possessing  great  strength,  combined  with  great  ductility,  are 
the  best  known  metals  for  constructive  purposes.  The  cast 
metal,  for  the  reasons  already  stated,  is  usually  worthless  for 
immediate  application  ;  but  could  it  be  produced  free  from 
porosity,  and  as  dense  as  the  forged  steel,  it  would  have  equal 
strength  and  ductility,  and  would  be  equally  applicable  foi 
use  in  structures  ;  it  would  also  have  the  important  advan- 
tages of  cheapness  and  of  facile  production  in  any  desired 
shape.  This  result  is  said  to  have  been  very  perfectly  secured 
at  Terrenoire  by  the  method  of  fluxing  above  alluded  to. 

Whitworth  secures  this  condition  by  subjecting  the  fluid 
steel  to  very  heavy  pressure  while  contracting  and  until  com- 
pletely solidified,  by  the  use  of  the  hydraulic  press.  A 
pressure  of  20  tons  to  the  square  inch  produces  all  of  the 
compactness,  density,  strength  and  ductility  of  a  forging.  By 
this  method,  Whitworth  has,  in  place  of  worthless  metal— as 
castings — produced  steel  of  tenacities  varying  in  the  several 
grades  from  80,000  pounds  per  square  inch  to  150,000  pounds, 
and  of  ductility  varying  from  35  per  cent,  in  the  softer  metal 
to  14  per  cent,  in  the  strongest  grade.  Guns  made  of  the 
softest  grade,  when  burst,  do  not  fly  in  pieces  as  cast  guns, 


MECHANICAL   TREATMENT  OF  THE  METALS. 


521 


invariably,  and  even  wrought-iron  guns  very  generally,  do, 
but  simply  open  along  the  line  of  minimum  strength,  and 
thus  explode  with  comparative  safety  to  the  gun's  crew. 


FIG.  34.— WHITWORTH'S  PRESS  FOR  INGOT  METAL. 

Metal  shown  to  the  Author  by  Sir  Joseph  Whitworth,  in  1870, 
at  Manchester,  England,  as  a  product  of  this  process,  was 
very  remarkable  for  its  strength,  ductility  and  homogeneous- 
ness,  and  worked  under  the  tool  with  most  admirable  freedom 
and  uniformity. 

Whitworth  states   that  the  column  of  fluid   steel,  while 
solidifying  under  pressure,  shortens  an  inch  and  a  half  to 


522  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


each  foot  of  its  length.  The  fact  is  a  good  index  of  the 
value  of  the  process,  and  gives  some  idea  of  the  degree  of 
unsoundness  of  the  best  of  ordinary  castings.  The  change 


Enlarged  Section  through  A,  A. 


Vertical  Section.  Horizontal  Section  through  B,  B. 

FIG.  35.— INGOT  CAST  WITHOUT  PRESSURE. 

of  texture  due  to  compression  is  very  marked,  as  shown  in 
the  accompanying  engravings  *  and  is  readily  observed  by  the 
nost  inexperienced  eye.  The  only  special  precaution  de- 
manded in  the  use  of  this  method  is  to  so  arrange  the  plant 
that  the  molten  steel  may  be  put  under  pressure  before 

*  From  Whitworth  on  Guns  and  Steel. 


ME  CHA  NIC  A  L   TREA  TMEN  T  OF  THE  ME  TALS.          523 

solidification    has    commenced ;    the    requisite    strength   of 
moulds  must  also  be  secured.* 

290.  The  Lavroff  Process. — Bronze  and  brass  may  be 
treated  by  the  same  methods  which  are  seen  to  have  been  so 
successfully  adopted  in  working  steel,  and  with  no  less  im- 
portant gain  in  excellence  of  quality.  These  compositions 
are  peculiarly  liable  to  defects  arising  from  the  occlusion  of 
gas  and  by  the  formation  of  oxide  within  the  mass.  Copper 
has  a  very  great  affinity  for  oxygen  at  high  temperatures,  and 
the  very  best  of  copper-tin  and  of  copper-zinc  alloys,  if  made 


Transverse  Section  of  Steel  Ingot          Transverse  Section  of  Steel  Ingot 
Cast  in  the  Ordinary  Way.  Compressed  while  in  a  Fluid  State. 

FIG.  36. — INGOT. 


without  special  provision  against  such  injury,  are  seriously 
defective  from  these  causes.  The  strongest  piece  of  such 
composition  which  the  author  has  ever  made,  and  which  far 
exceeded  in  tenacity  any  gun  metal  or  any  other  metal 
approximating  to  the  same  composition,  was  visibly  and 
keenly  defective.  Treatment  with  phosphorus,  or  other 
oxygen-absorbing  element,  has  been  found  to  do  much  toward 
correcting  this  fault.  Could  a  perfect  absorption  of  oxygen 
be  effected,  the  almost  invariable  unsoundness  of  bronze  and 

*  See  Report  on  Machinery  and  Manufactures  at  the  Vienna  International 
Exhibition,  1873,  by  the  Author.     Washington,  1875.     Page  439. 


524  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

brass  castings  would  probably  be  prevented,  and  what  would 
now  be  thought  a  remarkable  combination  of  strength  and 
ductility  would  be  secured.  Muschenbroeck  gives  the  tenacity 
of  fine  copper  wire  at  about  90,000  pounds  to  the  square  inch 
(6,327  kgs.  per  sq.  cm.).  Cast  copper  rarely  reaches  a  tenacity 
of  20,000  (1,406  kgs).  Yet,  with  maximum  density  and  perfect 
purity,  the  one  should  be  as  strong  as  the  other. 

Compression  with  proper  fluxing  will  do  all  that  can  be 
done  toward  giving  castings  of  these  metals  a  maximum  of 
strength,  ductility  and  resilience.  Colonel  LavrofT,  of  the 
Russian  army,  has  applied  the  Whitworth  method  to  the 
making  of  cast  bronze  guns.  To  make  the  process  thoroughly 
complete,  it  is  only  necessary  that  the  metal  compressed 
should  have  been  previously  purified  by  effective  fluxing  be- 
fore pouring. 

Col.  Lavroff,  as  stated  by  Col.  Laidley  in  his  ordnance 
notes  (No.  xl.,  printed  by  the  Ordnance  Bureau  of  the 
United  States  War  Department),  places  the  flask,  in  which 
the  gun  is  to  be  cast,  in  a  pit  directly  beneath  the  cylinder  of 
a  hydraulic  press.  The  upper  end  of  the  flask 'is  closely 
capped  by  a  strong  plate  of  iron,  having  a  cylindrical  hole  in 
its  centre.  Through  this  opening  a  plug  of  sand  is  forced 
down  upon  the  molten  metal  by  the  hydraulic  press,  and 
enters  the  mass  of  fluid  bronze  two  inches  or  more,  producing 
the  required  degree  of  condensation.  With  such  pressures  as 
are  employed  for  steel,  the  improvement  in  the  quality  of 
bronze  would  be  expected  to  be  quite  as  marked  as  in  that 
metal. 

291.  Rolling  and  Forging". — Compression  and  "  work- 
ing"  metal  in  the  solid  state,  but  at  high  temperature,  is  the 
most  usual  method  of  not  only  giving  the  materials  of  con- 
struction their  shape,  but  also  of  improving  their  valuable 
qualities.  As  is  well  known  to  every  engineer,  all  the  metals 
are  found  to  gain  strength  with  hammering  and  rolling.  The 
strength  of  a  grade  of  iron  which  has  a  tenacity  of  50,000 
pounds  per  square  inch  of  section,  when  macje  into  bars  two 
inches  in  diameter,  becomes  gradually  increased  as  the  size 
of  the  bar  is  reduced  by  rolling,  until  a  one-inch  bar  of  the 


MECHANICAL   TREATMENT  OF  THE  METALS.          $2$ 

same  iron  is  found  to  have  a  tenacity  of  nearly  or  quite  60,000 
pounds  to  the  square  inch.  Copper  and  some  of  the  alloys 
may  be  similarly  improved  by  heating  to  a  moderately  high 
temperature  and  drawing  out  under  the  hammer,  or  in  the 
rolling  mill.  Cast  copper,  of  a  tenacity  of  20,000  pounds 
per  square  inch,  acquires  in  this  way  a  strength  of  40,000 
pounds  and  upward. 

292.  Hydraulic  Forging  and  Drop  Forging. — This 
process  is  not  always  effective,  however,  as  large  masses,  both 
welded  and  cast,  are  very  liable  to  contain  cavities,  even  after 
having  been  subjected  to  the  most  skilful  manipulation  in  the 
forge  or  the  rolling  mill.  The  most  effective  system  of  ham- 
mering is  likely  to  prove  inefficient,  where  applied  to  large 
pieces,  in  consequence  of  the  fact  that  the  inertia  of  the  mass 
attacked  will  often  cause  the  effect  of  the  blow  to  be  felt  only 
near  the  exterior,  the  internal  portions  remaining  after  treat- 
ment nearly  as  spongy  and  as  irregular  in  structure  as  before. 
The  comparatively  moderate,  but  pervading — there  is  no  bet- 
ter word — effect  of  the  heaviest  hammer,  is  best  adapted  to 
do  such  work.  The  best  of  all  methods  of  securing  thorough 
condensation,  in  the  process  of  forging  small  pieces  which  can 
be  so  treated,  is  that  in  which  the  hydraulic  press  with  its  slow 
action,  producing  an  effect  which  is  felt  throughout  the  entire 
volume  of  the  piece,  is  employed.  This  process  has  been  well 
developed  by  Mr.  R.  L.  Haswell,  at  Vienna,  and  is  fully  de- 
scribed by  Prof.  W.  P.  Blake  in  his  report  on  iron  and  steel 
at  the  Vienna  Exhibition  of  1873.* 

The  process  of  making  forging,  with  the  "  drop  press," 
which  has  attained  greatest  perfection  in  this  country,  and  in 
which  the  piece  is  shaped  in  a  die  by  a  single  heavy  blow,  is 
also  thoroughly  satisfactory  as  applied  to  small  pieces.  The 
system  of  hydraulic  forging  is  most  economical  of  power,  as 
it  has  been  shown  by  Prof.  Kick  that  the  loss  of  power, 
wherever  shock  is  employed  in  such  work,  is  serious.  It  is 
wasted  by  dispersion  in  all  directions  in  the  form  of  heat,  due 
to  compression  and  to  directly  produced  tremor  of  molecules, 

*  Reports  of  the  U.  S.  Commissioners  to  Vienna  International   Exhibition, 
1873.     Washington,  1876.     4  vols.  8vo,  pp.  3,500. 


526  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

and  in  the  jar  and  shake  which  affects  all  neighboring  masses. 
The  quiet,  steady  action  of  the  hydraulic  press  accomplishes 
the  desired  change  of  form  without  the  latter  kind  of  loss  of 
energy,  and  with  a  minimum  loss  of  power  from  the  produc- 
tion of  heat  by  molecular  motion. 

293.  Thermo-Tension  and  Annealing. — Defects  of  homo- 
geneousness  of  structure  may  thus  be  removed,  partially  or 
wholly,  by  several  known  processes  of  treatment  of  heated 
metal.  Defect  of  homogeneousness  as  to  strain  is  removable 
from  iron,  and  perhaps  from  other  metals,  by  annealing  and 
by  a  method  called  in  1836,  by  its  discoverer,  Prof.  Walter 
Johnson,  "  thermo-tension."  The  metal  is  heated  to  a  full 
red  heat,  but  with  great  care  to  avoid  a  temperature  so  high 
as  to  give  rise  to  danger  of  serious  reduction  of  strength  by 
approaching  the  welding  heat.  At  this  elevated  temperature 
it  is  subjected  to  a  tensile  stress  of  as  great  intensity  as  is 
safe.  The  metal  is  then  allowed  to  cool,  retaining  the  stress 
applied,  and  when  cold  it  is  released.  Prof.  Johnson  found  this 
process  to  confer  upon  the  iron  experimented  with  a  maxi- 
mum resistance  to  change  of  form  exceeding,  by  about  16  per 
cent.,  that  which  it  had  originally  possessed.  He  offered  no 
explanation  of  the  molecular  change  to  which  the  effect  noted 
was  due  ;  but  it  has  been  attributed  by  the  Author  to  a  release 
of  internal  strains  which  had  previously  been  introduced  by 
the  irregularly  produced  flow  of  the  metal  occurring  during 
the  processes  of  manufacture. 

Cast  metals,  glass,  and  other  materials  which  have  been 
given  form  by  fusion,  casting  in  moulds  and  solidification 
which  so  occurs  as  to  produce  irregular  contraction  and  a  con- 
sequent unsymmetrical  distribution  of  metal,  and  which  are, 
therefore,  found  to  be  weakened  by  the  presence  of  internal 
strains,  are  relieved  of  such  internal  strain  by  the  familiar 
process  of  annealing.  The  more  brittle  the  material,  the  more 
carefully  and  slowly  must  the  process  of  annealing  be  conduct- 
ed. The  more  ductile  the  metal  and  the  greater  the  freedom 
with  which  it  is  found  to  "  flow"  under  the  action  of  applied 
forces,  the  less  serious  are  these  strains,  and  the  less  important 
is  the  process  of  annealing. 


MECHANICAL   TREATMENT  OF  THE  METALS.          $2? 

294.  Cold  Working. — Metals  are  worked  perfectly  cold 
in  some  cases,  and  the  several  methods  of  treatment  at  the 
ordinary  temperature  may  be  divided  into  two  classes : 

(i.)  Those  which  are  practised  for  the  purpose,  simply, 
of  conferring  greater  density,  and  of  thus  securing  homo- 
geneousness  of  structure. 

(2.)  Those  which  are  adopted  for  the  purpose  of  modify- 
ing the  character  of  the  metal  in  respect  to  internal  strains, 
and  thus  of  altering  the  normal  elastic  limit  of  the  material 
by  the  intermittent  application  of  external  forces. 

Cold  working  is  illustrated  in  the  processes  of  wire  draw- 
ing, cold  hammering  and  cold  rolling,  simple  compression,  and 
simple  extension  of  metal  without  heating.  The  effect  of 
either  of  the  processes  involving  compression  will  assign  the 
process  to  the  one  or  the  other  of  the  two  classes,  according 
to  the  nature  of  the  material.  It  may  be  that  the  same 
remark  will  be  found  applicable  to  all  methods  of  cold 
working. 

295.  Wire  Drawing. — The  process  of  wire  drawing  is  the 
oldest  and  most  generally  familiar  of  these  methods  of  treat- 
ment of  the  useful  metals.     In  the  manufacture  of  wire,  the 
metal  is  rolled  down  into  rods  a  quarter  of  an  inch  or  less  in 
diameter,  which  rods  are  called  "  wire  rods."     These  rods  are 
then,  in  the  wire  mill,  drawn  through  holes  in  steel  plates,  each 
of  which  holes  is  slightly  smaller  in  diameter  than  the  wire 
to  be  passed  through   it.     As  the  wire  is  reduced  in  size,  it 
gradually  becomes  hardened,  and,  at  intervals,  the  process  is 
interrupted,  and  the  metal  is  subjected  to  the  process  of  an- 
nealing to  soften  it,  and  thus  to  enable  the  decrease  in  size 
to  be  carried  on  without  the  serious  loss  of  power  and  risk  of 
breaking  which  would  otherwise  be  met.     As  the  decrease  of 
diameter  progresses,  the  wire  is  found  to  exhibit  a  gradual 
increase  in  tenacity,  which  increase  becomes  very  great  when 
the  wire  is  drawn  very  fine. 

Brass,  and  probably  all  other  metals  and  alloys  which 
have  the  requisite  qualities  to  permit  them  to  be  worked  by 
this  process,  are  similarly  increased  in  tenacity  by  the  action 
of  the  draw  plate.  The  precise  combination  of  qualities 


528   MATERIALS  OF  ENGINEERING—  XON-FERROUS  METALS. 

which  best  fits  metal  for  making  fine  wire,  has  never  been 
exactly  determined.  It  is  not  sufficient  that  the  metal  have 
simple  tenacity,  or  tenacity  and  malleability,  or  even  duc- 
tility, in  the  unlimited  sense  in  which  that  term  is  often  ap- 
plied. The  observations  and  experiments  of  the  writer  have 
led  him  to  suppose  that  perfect  homogeneousness  of  compo 
sition,  freedom  from  foreign  substances,  such  as  cinder  in 
iron  and  oxide  in  copper  and  its  alloys,  and  a  high  ratio  of 
tenacity  to  resistance  at  the  limit  of  elasticity  are  requisite. 
Some  metals  which  have  exhibited  great  strength  and  also 
very  great  ductility,  when  tried  in  the  testing  machine,  have 
failed  to  work  well  when  it  has  been  attempted  to  draw  them 
into  fine  wire.  Those  irons  which  have  been  drawn  as  fine  as 
No.  36,  or  even  to  No.  40,  have  usually  been  marked  by  a 
limit  of  elasticity  much  lower  than  other  very  fine  metals  of 
equal  tenacity  and  equal  ductility  as  indicated  by  their  be- 
havior in  the  testing  machine.  No.  40  wire  has  a  diameter 
of  0.003  incn  =  1~13>  or  0.078  millimetre.  (See  Part  II., 
Iron  and  Steel.) 

296.  Cold  Rolling— The  Lauth  Process.— As  has  been 
above  stated,  it  is  occasionally  necessary  to  anneal  wire 
during  the  process  of  drawing,  as  it  is  rendered  too  hard  to 
work  without  this  treatment.  This  increase  in  the  hardness 
of  the  metal  is  also  accompanied  by  an  increase,  equally 
marked,  in  the  elasticity  of  the  wire  ;  and  this  change  in  the 
character  of  the  material  is  quite  independent  of  the  simple 
strengthening  which  is  seen  in  even  the  annealed  wire.  Any 
process  of  compression  at  low  temperature,  properly  con- 
ducted, will  exhibit  the  latter  effect.  Hammering  metal  at 
the  ordinary  temperature  is  sometimes  resorted  to  to  give  it 
an  increased  hardness  and  elasticity.  The  same  process  is 
also  practised  to  confer  upon  forgings  a  smooth  and  hard 
surface.  If  not  intelligently  executed,  this  process  is  liable  to 
weaken  the  mass  by  extending  the  exterior  portions,  and 
thus  straining  the  inner  parts.  Where  practicable,  it  is  prob- 
ably better  to  use  the  hydraulic  press  in  doing  this  work. 

A  process  technically  called  "  cold  rolling "  has  been 
adopted  to  give  increased  stiffness  and  elasticity  to  iron, 


MECHANICAL   TREATMENT  OF  THE  METALS. 


529 


steel  and  other  metals  intended  for  certain  special  purposes,  as 
for  shafting,  for  the  finger  bars  of  reaping  machines,  and  for 
other  parts  of  machinery  intended  to  have  great  stiffness  and 
very  perfect  elasticity. 

FIG.  37. — EFFECT  OF  COLD  ROLLING. 


The  precise  temperature  at  which  this  effect  can  be  pro- 
duced has  not  been  determined.  It  is  within  a  range  which 
extends  nearly,  if  not  quite,  up  to  a  full  red  heat.*  Prof. 
Johnson  and  Mr.  Fairbairn  found  that  the  cohesion  of 
wrought  iron  was  practically  unaffected  at  a  temperature  of 

*  See  Metallurgical  Review,  Oct.  17,  pp.  159-162. 
34 


530   MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

six  hundred  degrees  Fahrenheit,  and  this  may  be  taken  as 
evidence  that  the  effect  of  cold  rolling  is  attainable  at  tem- 
peratures exceeding  the  black  heat. 

This  process  and  its  effects  upon  iron  have  been  described 
in  Part  II.  The  accompanying  strain-diagrams,  Figure  37,  ex- 
hibit this  effect,  and  may  be  taken  as  illustrative  of  the  effect 
of  the  process  on  all  metals,  and  especially  the  bronzes  to  be 
referred  to. 

297.  The  Dean  Process — Cold  Working  Bronze  has 
been  practised  in  the  United  States  by  Mr.  S.  B.  Dean,  and 
in  Europe,  on  a  more  extended  scale,  by  General  Uchatius, 
of  Vienna.  These  experimenters  endeavored  to  apply  the 
process  to  the  manufacture  of  bronze  ordnance,  and  used  the 
same  general  method  of  adapting  it  to  the  work. 

This  method,  as  described  by  the  inventor,  Mr.  Dean,  in 
1869,  is  the  following:  The  gun  is  "  placed  in  a  frame,  or 
upon  a  bed  somewhat  like  a  boring  mill  for  guns,  but  instead 
of  using  a  bar  provided  with  cutters,  there  is  fixed  in  the  end 
of  the  bar  a  smooth  cylindrical  plug  of  hardened  steel  about 
5-100  of  an  inch  larger  than  the  diameter  of  the  reamed  hole 
in  the  gun.  The  plug  should  be  made  of  two  frustra  of  cones 
with  their  bases  connected  by  a  short  cylinder. 

"  For  condensing  the  bores  of  rifled  guns,  the  plugs  used 
should  have  ribs  to  correspond  with  the  grooves  previously 
made  by  the  rifling  machine. 

"  The  bore  being  well  lubricated,  the  steel  plug  is  made  to 
traverse  the  bore  by  a  screw  or  other  suitable  means  till  it 
reaches  the  bottom  of  the  bore,  proper  provision  being  made 
to  allow  air  and  excess  of  the  lubricant  to  escape  through  a 
vent  in  the  plug  or  at  the  bottom  of  the  bore.  Instead  of 
forcing  a  plug  or  plugs  from  the  muzzle  to  the  bottom  of  the 
bore,  the  condensation  may  be  performed  by  commencing  at 
the  bottom  of  the  bore  and  drawing  the  plug  outward  ;  in 
which  case  the  plugs  should  be  so  made  as  to  be  expansible. 
After  the  first  plug  has  been  removed  from  the  bore,  two  or 
more  similar  plugs  are  successively  forced  through,  enlarging 
the  bore  to  the  desired  size. 

"  Care  should  be  taken  that  each  succeeding  plug  shall 


MECHANICAL  TREATMENT  OF  THE  METALS.          531 

have  a  diameter  slightly  larger  than  the  one  preceding  it,  and 
each  plug  should  perform  a  slightly  smaller  amount  of  com- 
pression than  the  preceding  plug,  on  account  of  the  increas- 
ing hardness  and  density  of  the  bore,  which  increases  the 
resistance  to  be  overcome  by  each  successive  plug." 

Dean  found  the  effect  of  this  treatment  to  be  very  marked 
in  increasing  the  hardness,  strength  and  density  of  bronze. 

A  cylinder  of  metal  taken  from  the  sinking  head  of  a 
bronze  gun  having  originally  a  specific  gravity  of  8.321,  a 
tenacity  of  27,238  pounds  per  square  inch  (19  kilograms  per 
square  millimetre),  and  a  hardness,  by  the  scale  used  by 
General  Rodman,  of  I,  was  given  a  tenacity  of  41,471  pounds 
per  square  inch  (29  kilograms  per  square  millimetre).  Its 
hardness  was  increased  to  2.97.  Its  density,  in  a  ring  one- 
quarter  inch  thick,  next  the  bore,  was  made  8.780.  In  the 
innermost  thickness  of  one-eighth  inch  it  was  8.875  ;  and  the 
density  of  a  circular  piece  one-quarter  inch,  taken  across  the 
bore,  was  8.595.  The  increase  here  noted  of  50  per  cent,  in 
tenacity  by  compression  has  been  exceeded  by  other  experi- 
menters. 

General  Uchatius,  the  director  of  the  arsenal  at  Vienna, 
has  reduced  this  process  to  practice  in  the  manufacture  of 
guns  for  the  Austrian  army ;  and,  as  he  informed  the  Author 
by  a  note  dated  June,  1875,  the  official  action  of  the  Com- 
mittee on  Artillery  resulted  in  the  promulgation  of  the  order 
that  "  steel  bronze  " — the  name  given  by  General  Uchatius  to 
the  new  product — "  is  to  be  accepted  as  gun-metal  in  the 
Austrian  army."  The  process  of  investigation  and  its  re- 
sults are  given  to  the  Author  by  Uchatius  substantially  as 
follows :  * 

298.  Uchatius'  Methods  of  Treating  Bronzes.— Ordi- 
nary bronze  for  guns  is  an  alloy,  consisting  of  about  90  parts, 
by  weight,  of  copper,  and  10  parts  of  tin.  Since  the  atomic 

*  See  the  report  by  the  Author  to  the  President  of  the  United  States  "  On 
Machinery  and  Manufactures,  with  an  Account  of  European  Manufacturing 
Districts;"  contained  in  the  reports  of  Scientific  Commissioners  of  the  United 
States  to  the  Vienna  International  Exhibition,  1873.  Published  under  the 
direction  of  the  Secretary  of  State  at  Washington,  1875.  Also,  see  report  of 
Colonel  T.  S.  Laidley,  in  "Ordnance  Notes,"  No.  XL." 


$32  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

weight  of  copper  is  63.4,  and  that  of  tin  118,  the  above  pro- 
portions of  the  alloy  correspond  to  a  combination  of  I 
equivalent  of  tin  with  17  equivalents  of  copper.  Experiment 
shows  us  that  it  is  questionable  whether  these  two  metals 
form  a  chemical  compound  in  these  atomic  proportions. 
When  large  molten  masses  of  this  alloy  solidify,  an  alloy  which 
is  poorer  in  tin  begins  to  crystallize  first  where  it  touches  the 
mould,  its  composition  being  about  92  parts,  by  weight,  of  cop- 
per, and  8  parts  of  tin,  or  I  equivalent  of  tin  to  21  equivalents 
of  copper ;  while  an  alloy  richer  in  tin  is  pressed  from  the 
former,  and  solidifies  last.  This  latter  alloy,  then,  forms  in 
the  inside  of  the  casting,  and  also  enters  the  cracks  which 
sometimes  form  in  the  outer  walls. 

This  behavior  in  the  fusion  of  alloys  rich  in  tin  was  also 
noticed  in  the  researches  on  alloys  of  copper  and  tin  made  by 
Alfred  Riche.*  M.  Riche  noticed  that  all  alloys  of  copper 
and  tin,  except  those  whose  compositions  correspond  to  the 
formulas  SnCu3  and  SnCu5,  undergo  refusion  at  the  moment 
of  solidification.  An  alloy  richer  in  tin  is  separated,  so  that 
different  compounds  are  to  be  found  at  different  points  in 
the  casting.  When  the  alloy  consists  of  tin  and  copper  in  the 
proportion  of  I  to  5,  this  refusion  occurs  to  but  a  slight  extent, 
but  when  the  composition  is  different  it  becomes  very  serious. 

As  a  proof  of  the  occurrence  of  these  conditions  in  alloys, 
it  may  be  stated  that  rich  bronze  of  a  very  homogeneous 
character  is  always  found  in  the  smaller  parts  of  bronze  cast- 
ings ;  for  example,  in  the  cascabel,  or  in  the  trunnions  of  a  gun. 
This  bronze  contains  about  8  per  cent,  of  tin,  while  the  body 
of  the  gun  is  permeated  by  thin  sheets  of  tin.  An  8-inch 
tube  was  made  at  the  Royal  Imperial  Arsenal,  for  which 
28,000  kilograms  (61,600  pounds)  of  metal  were  employed. 
The  greatest  diameter  of  this  casting  was  about  0.84  m.  (33 
in.),  and  the  proportion  of  tin  at  this  part  was  8  per  cent,  on 
the  outside  and  12  per  cent,  on  the  inside. 

Bronze  with  8  per  cent,  of  tin  has  not  yet  been  employed 
for  guns,  because  its  wear  is  greater  than  that  of  10  per  cent, 
bronze.  "  Gun-metal  "  has  long  been  employed  because  of 

"  Annales  dc  Chimie  et  de  Physique"  tome  30. 


MECHANICAL   TREATMENT  OF  THE  METALS.          533 

its  great  tenacity  and  consequent  safety,  and  because  it  has 
the  advantage  of  cheapness  and  ease  in  working.  Its  strength 
has  satisfied  the  demand  nearly  up  to  the  present  time,  and 
it  has,  therefore,  been  retained  in  the  manufacture  of  field- 
pieces,  in  spite  of  its  tendency  to  "  bulge  "  and  to  burn  out. 
Modern  practice,  however,  will  no  longer  permit  its  applica- 
tion as  formerly. 

From  an  accompanying  table  of  properties  of  types  of 
gun-bronze,  we  find  those  of  ordinary  gun-bronze,  as  com- 
pared with  Krupp's  steel  for  guns,  to  be — 


BRONZE. 

STEEL. 

Tenacity.             

2,260    kilograms     per   square 

4  800  kilograms  (68  160  Ibs  )• 

Elastic  resistance  

centimetre  (32,092  pounds  per 
square  inch). 
400  kilograms  per  square  cen- 

Extension when  broken. 

timetre    (5,680    pounds    per 
square  inch). 
15  per  cent. 

Hardness  ^depth  of  indenture) 

12.5  millimetres  (%  inch). 

10.5  millimetres  (.42  inch). 

We  see  that  the  tenacity  as  well  as  the  limit  of  elasticity 
of  cast  steel  is  almost  twice  as  great  as  that  of  ordinary 
bronze,  which  has  even  less  ductility  than  steel.  If  the  prop- 
erties of  bronze  could  not  be  further  improved — wrought 
iron  being  unreliable  as  gun-metal — we  would  necessarily  be 
compelled  to  accept  steel.  But,  fortunately,  new  wants  are 
generally  supplied  in  time  by  the  progress  of  science  and  art. 

A  new  modification  of  gun-bronze,  which  is  much  su- 
perior to  ordinary  gun-bronze,  according  to  Uchatius'  table 
of  gun-metals,  is  now  made,  for  which  General  Von  Uchatius 
has  proposed  the  name  4<  steel-bronze,"  on  account  of  the 
resemblance  of  its  properties  to  those  of  cast-steel. 

If,  instead  of  employing  sand,  we  use  iron  chills  of  a  cor- 
responding thickness  of  material,  the  process  of  solidification 
takes  place  with  such  rapidity  that  the  alloy  rich  in  tin  cannot 
separate,  and  the  bronze  becomes  perfectly  homogeneous. 

The  strength  rose  to  3,050  kilograms  (43,210  pounds  per 
square  inch),  the  elastic  limit  remained  at  400  kilograms,  the 
hardness  (depth  of  indenture)  at  12.5  millimetres,  .5  inch), 
while  the  amount  of  stretch  before  breaking,  or  the  ductility 


534  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

of  the  material,  rose  to  40  per  cent.  These  improvements  in 
the  quality  of  bronze  are  a  step  forward  in  bronze-casting, 
but  it  is,  nevertheless,  not  sufficient  to  satisfy  modern  require- 
ments. A  gun-barrel  cast  in  this  manner  would  not  burst,  as 
the  ductility  of  the  material  (40  per  cent.)  is  enormous ;  but  it 
would  not  be  capable  of  resisting  the  pressure  of  the  gas  ; 
and,  since  the  elasticity  is  not  greater  than  with  ordinary 
bronze,  the  gun-barrel  would  "  bulge."  The  hardness  also 
remained  unchanged,  and  it  is  therefore  not  great  enough  to 
cut  the  grooves  in  the  sabots  of  the  shot. 

General  Von  Uchatius  next  tried  to  roll  a  piece  of  the 
chilled  bronze  cold.  This  could  be  done,  although  consider- 
able power  was  necessary.  Not  the  slightest  crack  was  pro- 
duced, even  when  stretched  to  the  amount  of  100  per  cent,  of 
its  original  length.  When  the  bronze  had  stretched  20  per 
cent.,  it  attained  the  strength,  hardness,  and  elasticity  of 
steel.  The  figures  are  as  follows  : 

The  tenacity,  5,066  kilograms  per  square  centimetre, 
(71,937  pounc^  per  square  inch). 

The  elastic  resistance,  1,700  kilograms  per  square  centi- 
metre (24,140  pounds  per  square  inch). 

The  hardness  (depth  of  indenture),  10.2  millimetres  (.41 
inch). 

It  is  evident  that  if  this  characteristic  of  chilled  bronze, 
of  assuming  the  properties  of  steel,  when  rolled,  could  be  em- 
ployed on  the  inner  surface  of  gun-barrels,  the  process  would 
be  of  great  value.  On  examining  the  table  of  gun-metals, 
he  remarks  the  peculiarity  that  all  tough  metals  assume  a 
much  higher  elasticity  when  they  are  stretched  beyond  the 
elastic  limit,  which  fact  had  already  been  noted  by  Dean. 

In  this  fact  we  may  find  the  explanation  of  a  well  known 
phenomenon,  often  observed.  A  bronze  barrel  which  was  not 
strong  enough  to  resist  the  charge,  and  which,  therefore, 
"  bulged,"  still  approximately  retained  its  form  after  long- 
continued  use.  It  could  even  be  reduced,  by  turning  off  the 
outside,  without  losing  its  resisting  power.  The  natural 
chilled  bronze  has  its  limit  of  elasticity  at  400  kilograms, 
(5,680  pounds  per  square  inch),  and  permits  a  stretch  of  0.0004 


MECHANICAL  TREATMENT  OF  THE  METALS.          535 

of  its  length ;  while  if  a  permant  set  of  0.00441  of  its  length 
is  produced,  its  elastic  limit  becomes  1,600  kilograms  (22,720 
pounds  per  square  inch),  and  its  stretch  within  the  elastic 
limit,  0.00192.  The  rolled  chilled  bronze  attains  its  limit 
of  elasticity  at  1,700  kilograms  (24,140  pounds  per  square 
inch),  and  has  an  elastic  extension  of  0.0017  of  its  length, 
while  a  permanent  stretch  of  0.00018  of  its  length  raises 
the  limit  of  elasticity  to  2,400  kilograms  (34,080  pounds  per 
square  inch)  and  its  elastic  extension  to  0.00252. 

This  advantage  is  as  great  with  steel,  wrought  iron,  and 
in  general  all  extensible  metals,  but  it  has  never  been  taken 
advantage  of  in  the  manufacture  of  guns,  until  Dean  and 
Uchatius  made  the  application. 

The  following  principle  was  enunciated  by  General  Von 
Uchatius  as  a  theory  of  working  a  gun-barrel  from  a  homo- 
geneous, very  ductile,  and  tough  metal.  It  is  based  upon 
results  obtained  by  precise  measurements  of  the  properties 
of  the  metals : 

/.  The  work  performed  by  the  pressure  of  the  gases  of  the 
exploded  powder,  and  destroying  the  fit  of  the  shot  by  enlarging 
the  bore,  sliould  be  performed  origin-ally  by  mechanical  means, 
and  to  a  far  greater  extent  than  will  be  produced  by  the  heaviest 
charge.  By  this  means  the  elastic  limit  of  the  metal  of  the 
barrel  is  increased  to  such  an  extent  that  the  smaller  press- 
ures of  gas  produced  in  discharging  the  gun  have  no  effect. 

//.  The  surface  of  the  bore  must  be  submitted  to  a  process 
resembling  rolling  to  such  an  extent  as  to  give  it  the  necessary 
hardness. 

By  this  process  of  mechanical  working  of  the  casting  the 
material  is  not  overstrained.  Its  quality  is  not  injured ;  on 
the  contrary,  as  this  extension  goes  on  in  the  cold  state,  the 
molecules  take  new  and  stable  positions,  refining  the  metal. 
Its  properties  are,  therefore,  improved. 

Before  proceeding  fo  the  method  of  working  on  the  cast- 
ing, it  was  necessary  to  solve  two  very  important  problems, 
namely : 

Which  alloy  of  copper  and  tin  is  best  suited  for  chilled 
casting  ? 


MATERIALS  OF  ENGINEERING-NON-FERROUS  METALS. 

How  can  the  quality  of  the  metal  at  the  inside,  or  nearest 
the  bore,  be  made  to  correspond  to  that  of  the  alloy  at  the 
outside,  so  that  the  metal  can  be  subjected  to  the  process  of 
rolling  ? 

In  order  to  determine  the  best  alloy,  a  small  cast-iron  chill 
was  made,  of  25  millimetres  (i  inch)  and  50  millimetres  (2 
inches)  width  in  the  clear,  and  25  millimetres  (i  inch)  thick- 
ness of  sides,  into  which  the  following  alloys  were  cast : 

12  per  cent,  bronze. 

10  per  cent,  bronze. 
8  per  cent,  bronze. 
6  per  cent,  bronze. 

10  per  cent,  bronze,  with  2  per  cent,  addition  of  zinc. 

10  per  cent,  bronze,  with  I  per  cent,  addition  of  zinc. 

8.5  per  cent,  bronze,  with  ^  per  cent,  addition  of  zinc. 

The  last  of  these  alloys  is  that  which  Lavissiere  exhibited 
at  the  Vienna  Universal  Exposition  of  1873,  and  which 
attracted  attention  by  its  uniform  and  homogeneous  appear- 
ance and  by  its  peculiarly  excellent  quality. 

Two  rods  were  cut  from  each  of  the  castings,  and  these 
were  rolled  out  until  they  acquired  the  hardness  of  "  mild  " 
steel.  It  became  evident,  during  this  process,  that  the  12 
per  cent,  bronze  could  not  bear  rolling,  and  the  tests  were 
limited  to  the  remaining  alloys. 

It  was  found  necessary  to  continue  the  rolling  of  the  rods 
in  order  to  reach  the  hardness  of  steel ;  with  the 

10  per  cent,  bronze,  to  an  elongation  of  20  per  cent. 
8  per  cent,  bronze,  to  an  elongation  of  30  per  cent. 
6  per  cent,  bronze,  to  an  elongation  of  50  per  cent, 
with  the— 

10  per  cent,  bronze  and  2  per  cent,  zinc,  to  an  elongation 
of  10  per  cent. 

10  per  cent,  bronze  and  i  per  cent,  zinc,  to  an  elongation 
of  15  per  cent. 

8.5  per  cent,  bronze  and  J^  per  cent,  zinc,  to  an  elongation 
of  20  per  cent. 

The  results  of  tests  made  can  be  seen  in  the  following 
table : 


MECHANICAL   TREATMENT  OF  THE  METALS. 


537 


ALLOYS. 

TENSILE 
STRENGTH. 

ELASTIC  LIMIT. 

ELONGATION  WITHIN 
THE  ELASTIC  LIMIT  IN 
O.OOOOI. 

SET  IN  PER  CENT.  OF 
LENGTH. 

Pounds  per 
square  inch. 

Kilograms  per 
square  centi- 
metre. 

Poundsper 
square  inch. 

Kilograms  per 
square  centi- 
metre. 

10  per  cent,  bronze  

7  ',937 
73.840 
77,532 
42,884 
59.214 
53.900 

5,066 
5,200 

5.460 

3,020 

4,170 

3,800 

18,460 
8,520 
14,200 
21,300 

1,700 
1,400 
'•Soo 
600 

1,000 

I,500 

174 
I40 
128 
89 
120 
157 

1.5 
2-5 
3-5 
0-5 
o-7 

1.7 

8  per  cent   bronze     

6  per  cent  bronze 

zc  per  cent,  bronze  and  2  percent,  zinc  ... 
10  per  cent,  bronze  and  i  per  cent.  zinc.  .  . 
8.5  per  cent,  bronze  and  %  per  cent.  zinc. 

These  tests  showed  that,  in  general,  the  10  per  cent.,  as 
well  as  the  8  per  cent,  and  6  per  cent,  bronzes,  may  be  em- 
ployed in  the  new  method  of  making  gun-barrels,  while  the 
addition  of  zinc  is  of  no  use  whatever,  but,  on  the  contrary, 
decreases  its  value  in  no  inconsiderable  degree. 

The  8  per  cent,  bronze  was  judged  to  be  the  best  for  large 
castings,  and  this  has,  therefore,  been  taken  as  the  proper 
alloy  for  "  steel-bronze." 

A  number  of  trials  were  made  to  determine  what  method 
of  casting  and  cooling  would  make  the  inner  layers  of  the 
casting  homogeneous,  and  give  the  necessary  toughness  for 
standing  the  treatment  to  which  they  were  to  be  subjected. 

Simultaneously  with  these  trials,  those  castings  whose 
quality  was  shown  to  be  good,  by  the  appearance  of  the 
fracture,  were  subjected  to  the  mechanical  treatment.  A 
hydraulic  press  was  employed  for  this  purpose,  of  a  capacity 
of  IOO,OOO  kilograms  (220,000  pounds). 

The  following  is  a  short  sketch  of  the  main  features  of 
the  method  which  was  employed  for  making  gun-barrels  sub- 
sequently to  September,  1873: 

The  castings  were  260  millimetres  (10.4  inches)  thick,  300 
millimetres  (12  inches)  long,  having  a  bore  of  80  millimetres 
(3.2  inches)  diameter.  They  were  conical  and  turned  down  at 
one  end  to  180  millimetres  (7.2  inches)  diameter.  They  were 
then  placed  vertically  under  the  die  of  a  hydraulic  press, 
which  was  then  driven  through  them,  in  accordance  with  the 
Dean  system,  a  system  the  earlier  existence  of  which  General 


T7NIVERSITT 


538  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

Uchatius  seems  ignorant.  The  surface  of  the  die  was  of  well- 
hardened  steel,  and  was  a  slightly-tapering  cone,  thus 
increasing  the  diameter  gradually.  But,  since  the  resistance 
increased  with  the  enlargement  of  the  barrel,  the  difference 
between  the  diameter  of  the  plunger  and  that  of  the  last 
formed  barrel  must  decrease  gradually.  Six  plungers  were 
employed  in  succession,  of  which  the  first  increased  the  bore 
by  2  millimetres  (.08  inch)  and  the  last  by  y2  millimetre  (.02 
inch). 

The  original  diameter  of  the  bore,  80  millimetres  (3.2 
inches),  was  thus  increased  to  its  normal  size  of  87  milli- 
metres (3.88  inches) ;  that  is  the  increase  amounted  to  7 
millimetres  (.28  inch),  or  8.75  per  cent.,  while  the  exterior 
diameter  of  the  casting  was  increased  by  2  per  cent.  The 
surface  of  the  bore  which  was  thus  produced  had  a  hardness, 
when  measured  by  indentation,  of  10.5  millimetres  (.42  inch), 
or  equal  to  that  of  gun-steel ;  it  was  as  smooth  as  a  mirror, 
and  only  needed  rifling.  It  was  further  remarked  that  the 
same  result  as  to  hardness  was  produced  at  the  end  which 
was  weakened  by  turning  down,  which  would  seem  to  indi- 
cate that  the  outer  layers  of  guns  do  not  come  into  play  at  all 
when  firing. 

299.  Experiments  on  Compressed  Bronze. — The  mate- 
rial of  the  first  two  experimental  barrels  of  steel-bronze  had 
the  following  properties  : 


PROPERTIES   OF   STEEL-BRONZE. 

TEST-BARREL  NO.  X, 
NEAR   THE  — 

TEST-BARREL  NO.  2, 
NEAR   THE  — 

Bore. 

Exterior 
surface. 

Bore. 

Exterior 
surface. 

Tensile  strength  per  i  square  centimetre,  in  kilo- 
grams   

4^250 
6o,35° 

T,IOO 
15,620 

0.306 
0.56 

10.6 
.42 

3,32° 
47,M4 

500 
7,100 
50 
0.060 

0.50 

12 

.48 

4,25o 
60,350 

I,  TOO 

15,620 

16J 

0.306 

0.56 

10.6 
.42 

3,320 

47^44 

700 
9,940 

1°. 
0.060 

0.50 

12 

.48 

Tensile  strength  per  i  square  inch,  in  prunds  
Limit  of  elasticity   per   i  square  centimetre,  in 
kilograms  

Limit  of  elasticity  per  i  square  inch,  in  pounds  .  . 
btretch,  ultimate,  in  per  cent,  of  length 

Stretch,  elastic,  in  per  cent,  of  length  
Section  at  the  point  of  rupture,  which  was  orig- 
inally taken  —  i.oo 

Hardness,  depth  of  indenture,  in  millimetres  
Hardness,  depth  of  indenture,  in  inches  

MECHANICAL  TREATMENT  OF  THE  METALS.          539 

Both  barrels  were  subjected  to  tests  by  firing. 

These  tests  were  made  on  the  "  Simminger  Haide,"  from 
40  to  50  shots  being  fired  daily,  two  shots  with  the  diminished 
charge  of  I  kilogramme  (2.2  pounds),  and  238  shots  with  the 
normal  charge  of  1.5  kilogrammes  (3.3  pounds).  The  projec- 
tiles were  2^  diameters  in  length,  and  the  powder  used  for 
the  charge  was  large-grained  powder,  the  size  of  the  grains 
being  from  6  millimetres  to  10  millimetres  (0.24  inch  to  0.4 
inch),  the  density  was  1.605. 

The  barrel  showed  no  signs  of  either  a  widening  of  the 
bore  or  any  other  flaw  after  these  tests. 

The  test-barrel  No.  2  was  tried  on  the  "  Steinfelder  Haide" 
to  determine  the  decrease  in  precision  of  firing  consequent 
upon  the  firing  a  great  number  of  shots  with  the  charge  of 
1.5  kilogrammes  (3.3  pounds),  and  with  projectiles  2^2  diam- 
eters in  length,  weighing  6^  kilogrammes  (14  pounds).  The 
velocity  attained  with  this  charge  was  1,480  feet.  In  all, 
2,130  solid  shot  were  fired  and  twenty  shells  were  thrown. 

The  examination  of  the  barrel  showed  the  chamber  to  be 
quite  unaltered.  The  enlargement,  which  was  perceptible — 
about  o.  I  millimetre  (0.004  inch) — was  due  to  burning  out 
and  to  mechanical  wear.  The  lands  and  grooves  of  the  bar- 
rel were  worn  considerably,  after  this  great  number  of  dis- 
charges, by  mechanical  wear  and  by  burning  out,  but  from 
the  muzzle  to  the  vicinity  of  the  trunnions  the  lands  were 
left  quite  sharp,  and  consequently  were  capable  of  seizing 
the  projectile  with  perfect  accuracy,  giving  the  necessary 
stability  in  the  barrel. 

After  2,100  discharges,  a  projectile  was  purposely  made 
to  burst  in  the  gun,  in  order  to  determine  the  amount  of 
damage  thus  produced  and  its  effect  upon  the  accuracy  of  fit 
of  the  shot.  The  following  series  of  25  shots  did  not  show 
loss  of  accuracy,  although  the  grooves  and  lands  were  badly 
damaged,  for  the  latter  were  crushed  and  the  metal  squeezed 
into  the  grooves. 

This  method  of  working  castings  applies  advantageously 
to  the  production  of  steel  gun-barrels.  Steel,  having  an  elas- 
tic limit  of  2,000  kilogrammes  per  square  centimetre  (28,400 


54°  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

pounds  per  square  inch)  and  a  ductility  of  20  per  cent.,  can- 
not be  produced  by  any  hardening  process  or  method  of 
manufacture,  except  by  stretching  in  the  cold  state. 

300.  Uchatius'    Deductions. — The   steel-bronze   barrels 
will,  according  to  General  Uchatius,  prove  to  be  better  than 
those  of  steel,  for  the  following  reasons : 

On  account  of  the  quadruple  price  of  the  steel,  and  be- 
cause old  steel-bronze  barrels  can  always  be  remelted. 

On  account  of  the  time  required  in  manufacturing,  which 
with  steel  is  six  or  seven  times  as  long  as  that  needed  with 
steel-bronze.  In  order  to  produce  a  cast-steel  barrel  fitted 
with  rings,  the  inner  tube  is  first  cast.  It  is  then  heated  and 
worked  under  the  steam-hammer  ;  it  is  then  bored,  and  finally 
the  rings  are  shrunk  upon  it.  For  this  purpose  are  needed, 
not  only  very  costly  plant,  but  also  skilful,  experienced,  and 
very  reliable  workmen.  The  steel-bronze  barrels  are  simply 
cast,  then  bored  and  pressed,  and  finally  drawn  ;  all  of  which 
manipulations  are  very  simple. 

On  account  of  the  greater  rapidity  of  destruction  of  the 
steel  by  atmospheric  influences.  The  destructive  effect  of 
oxidation  rapidly  penetrates  to  the  interior  with  steel,  while 
steel-bronze  merely  receives  a  superficial  layer  of  verdigris, 
which  does  not  penetrate. 

Because  steel  barrels  are  not  as  safe  for  the  gun's  crew 
as  steel-bronze  barrels,  of  which  the  exterior  layers  are  so 
tough  that  they  must  be  stretched  50  per  cent,  before  fract- 
ure. 

The  cost  of  a  steel-bronze  barrel  thus  made  and  of  the 
size  here  described  is  given  as  $175,  and  that  of  a  gun  made 
of  steel  at  $750. 

301.  Frigo-Tension. — There  is,  finally,  another  process — 
which  is  applicable,  however,  only'to  ductile  iron  and  steel, 
and  to  such  other  metals  as  exhibit  an  elevation  of  any  nor- 
mal elastic  limit  by  the  intermittence  of  strain — which  maybe 
usefully  applied  at  ordinary  temperatures  with  the  result  of 
increasing  the  elastic  resistance,  and,  usually,  the  ultimate 
strength  of  the  material.     This  process  has  been  long  used 
by  bell-hangers  when  wishing  to  give  wire  greater  stiffness 


MECHANICAL  TREATMENT  OF  THE  METALS.          541 

and  uniformity  of  stretch ;  but  it  has  not  become  generally 
known  or  extensively  applied  in  the  arts. 

When  a  bar  of  copper,  zinc,  tin,  lead,  or  other  metal  than 
iron  or  steel,  is  subjected  to  gradually  increasing  distortion,  it 
offers  gradually  increasing  resistance  up  to  the  point  of  rupt- 
ure, and  this  resistance  follows  a  regular  law  in  most  cases, 
whether  the  distorting  force  is  applied  steadily  or  intermit- 
tently. This  gradual  increase  of  resistance  is  due  to  the  fact 
that  the  normal  elastic  limit  for  all  metals  becomes  higher  as 
distortion  progresses,  until  it  finally  coincides  with  the  ulti- 
mate strength  of  the  piece,  and  fracture  then  occurs. 

When,  during  the  process  of  extension,  the  stress  is  inter- 
mitted, the  effect  of  such  intermission,  as  has  been  seen,  Art. 
285,  is  often  to  produce  a  marked  change  in  the  position  of 
the  normal  elastic  limit  due  to  the  degree  of  stretch  attained, 
and  it  is  found  that  on  renewing  the  effort  to  distort  the 
piece,  the  limit  of  elasticity,  when  distortion  again  begins,  is 
not  precisely  where  it  was  at  the  interruption  of  the  process 
of  distortion.  In  some  cases  the  change  is  hardly,  if  at  all, 
observable ;  in  other  cases  the  elastic  limit  is  found  to  have 
been  elevated ;  and  in  still  other  cases,  where  the  load  has 
not  been  removed,  it  is  lowered.  This  difference  has  led  to 
the  division,  by  the  Author,  of  the  metals  used  in  construction 
into  two  classes.  One  comprehends  iron  and  steel,  and,  pos- 
sibly, other  metals  not  yet  determined.  The  other  class  com- 
prehends the  inelastic  metals,  including  copper,  tin,  zinc,  and 
their  alloys. 

302.  Comparison  of  Methods.— The  effects  of  the  several 
methods  of  working  which  have  been  described  can  be  well 
explained  and  illustrated  by  a  comparison  of  the  strain-dia- 
grams of  the  product  of  each. 

The  effect  of  the  processes  which  are  adopted  to  improve 
metals  by  treatment  before,  or  during,  solidification  after 
fusion,  is  to  give  greater  strength,  ductility,  elasticity,  and 
resilience.  The  strain-diagram  is,  therefore,  given  higher 
ordinates,  a  greater  maximum  abscissa  and  an  enlarged  area ; 
that  is,  the  diagram  of  the  untreated  metal  is  given  increased 
altitude,  an  increased  extension,  and  a  much  greater  area. 


542  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

The  general  character  of  the  diagram  remains  unchanged, 
except  as  to  dimensions,  unless  modified  by  peculiarities  of 
subsequent  treatment.  The  effect  is  the  same  in  kind,  to 
whichever  class  the  metal  may  belong.  It  is  the  same  with 
the  Whitworth  as  with  the  Lavroff  process.  The  treatment 
of  the  molten  metal  by  fluxing  before  subjecting  it  to  any 
mechanical  manipulation,  produces  the  same  modification  of 
the  strain-diagram.  A  combination  of  the  two  processes,  as 
the  addition  of  phosphorus  to  bronze,  with  compression  of  the 
metal  by  the  Lavroff  method,  would  evidently  give  a  still 
more  important  improvement  and  would  be  represented  by 
a  still  more  marked  change  in  the  strain-diagram. 

The  process  of  working  the  metals  at  a  red  heat,  as  in  the 
rolling  mill  and  in  the  forge,  effects  changes  which  are  in  gen- 
eral exhibited  on  the  strain-diagram  by  those  modifications 
which  indicate  increased  strength,  ductility,  resilience,  and 
homogeneousness  in  the  character  of  metals.  The  effect  is 
not  precisely  the  same  on  the  two  classes.  All  cast  and  un- 
worked  metals  give  a  strain-diagram  of  approximately  para- 
bolic form  and  free  from  any  sudden  change  of  curvature. 
Their  elastic  limits  are,  therefore,  modified  by  the  slightest 
distortion,  and  an  elastic  limit  is  found  at  the  zero  of  load 
and  of  strain.  This  was  first  explicitly  stated  by  Hodgkin- 
son,  when  reporting  on  his  experiments  on  cast-iron.  The 
strain-diagrams  published  by  the  Author  in  the  cases  already 
referred  to*  show  that  this  is  true  of  the  other  cast  metals. 
The  slightest  force  in  all  such  cases  produces  a  set. 

After  having  been  subjected  to  the  action  of  the  rolls  or 
of  the  hammer  at  a  red  heat,  the  inelastic  metals  of  Class  2 
give  the  same  smoothly  curved  diagram  as  before,  the  change 
being  observable  in  the  dimensions  and  not  in  the  form  of 
the  curve.  The  metals  in  Class  I,  however,  give  strain-dia- 
grams which  are  of  a  somewhat  different  form.  Instead  of 
the  form  O  E  A,  Fig.  38,  a  sharp  change  of  direction  is  seen 
at  some  point,  and  the  diagram  is  more  like  O  E  C.  The 
normal  elastic  limit  of  the  piece  when  tested  is  found  to  be 
at  first  rapidly  elevated  as  distortion  progresses,  until  at  some 

*  Part  II.,  Fig.  98 


MECHANICAL  TREATMENT  OF  THE  METALS. 


543 


point,  E,  a  sharp  change  of  the  ratio  of  the  distorting  force 
to  the  amount  of  coincident  distortion  takes  place,  and  the 
sets  become  approximately  equal  to  the  total  distortions. 
This  point  is  the  "  apparent  "  elastic  limit,  which  is  the  elastic 
limit  as  commonly  understood.  Rolled  or  forged  metals  of 
the  first  class,  therefore,  have  an  apparent  elastic  limit  which 
fs  much  more  clearly  marked  than  in  any  cast  metal,  or  in 
any  metals  of  the  second  class. 


FIG.  38. — STRAIN-DIAGRAMS. 

Thus,  in  Figure  38,  let  the  curves  A,  B,  and  C  represent 
the  strain-diagrams,  (i)  of  any  cast  metals,  (2)  of  a  rolled 
metal  of  the  second  class,  and  (3)  of  a  part  of  the  diagram  of 
rolled  iron,  respectively.  The  characteristic  differences  be- 
tween the  two  rolled  metals  and  between  them  and  the  cast 
metal  are  well  indicated.  These  curves  are  copied  from  actual 
diagrams  produced  automatically,  and  are  real  graphic  repre- 
sentations of  those  characteristics. 

The  depression  seen  at  D  is  an  indication  of  the  presence 
of  fibre  in  the  metal. 

303.  The  Effect  of  the  Processes  of  Rolling  and  of 
Hammering  the  metal  cold  are  graphically  represented  in 
Figure  39.  The  strain-diagram  A  is  a  copy  of  the  beginning 
of  that  given  in  the  Mechanical  Laboratory  of  the  Stevens 
Institute  of  Technology  by  a  piece  of  merchant  bar  iron  of 
excellent  quality.  That  marked  B  is  a  copy  of  the  initial 


544  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


portion  of  a  diagram  produced  automatically  by  a  sample  of 
cold-rolled  shafting  made  by  treatment  of  a  piece  of  iron 
of  similarly  good  quality.* 

It  is  seen  at  a  glance  that  the  effect  of  cold-rolling  is,  in 
this  case,  to  bring  the  apparent  elastic  limit  nearly  up  to  the 
maximum  of  resistance,  which  is  only  attained  in  the  un- 
treated metal  after  very  great  distortion.  As  has  already 
been  stated,  the  piece  also  exhibits  a  much  greater  ultimate 


FIG.  39.— STRAIN-DIAGRAMS  OF  IRON. 

resistance  than  the  same  metal  prepared  in  the  usual  way. 
The  resilience,  taken  at  the  elastic  limit,  is  immensely  in- 
creased, and  the  elasticity  of  the  metal  was  found  to  be  the 
same,  wherever  measured,  while  distortion,  was  progressing. 
The  metal  is  probably  compacted  to  some  extent,  but  to  so 
slight  a  degree  that  the  resulting  change  of  density  has  not  been 
measured.f  Examining  the  piece  after  fracture,  it  is  found 
that  concentric  layers  differ  from  each  other  in  the  degree  in 
which  they  exhibit  the  effect  of  cold-rolling,  but  that  in  each 
layer  the  metal  is  rendered  exceedingly  homogeneous.  As  in 
all  ordinary  work  the  metal  is  never  intended  to  be  perma- 

*See  plate,  above  referred  to,  Part  II.,  strain-diagram  No.  85;  see  also 
Report  by  the  Author  on  an  extensive  series  of  tests  of  cold-rolled  metal  for  the 
American  Iron  Works,  1877. 

f  Major  Wade  found  no  increase  of  density,  but  apparently  a  slight  decrease 
after  cold-rolling  iron. 


MECHANICAL  TREATMENT  OF  THE  METALS. 


545 


nently  distorted — is  never  expected  to  be  subjected  to  strains 
which  can  produce  permanent  set — the  increased  value  for 
constructive  purposes  which  is  conferred  by  this  treatment  is 
measured  by  the  increase  noted  in  its  strength,  elasticity, 
ductility  and  resilience  within  the  elastic  limit.  It  is  seen  to 
be  immensely  great.  The  effect  observed  is,  in  this  case,  due 
probably  to  the  elevation  both  of  the  apparent  and  the  nor- 
mal elastic  limit,  by  both  the  simple  condensation  and  in- 
crease of  horn ogeneojusn ess  which  occurs  with  metals  of  the 


FIG.  40. — STRAIN-DIAGRAMS  OF  BRONZES. 

second  class,  and  by  that  peculiar  exaltation  of  tenacity,  by 
some  as  yet  not  fully  determined  change  in  molecular  rela- 
tions, which  is  only  known  to  take  place  with  metals  of  the 
first  class. 

The  effect  of  the  cold-rolling  process  is,  however,  the 
same  in  kind,  so  far  as  it  affects  the  form  of  the  strain-dia- 
gram, where  the  second  class  of  metals  is  treated,  and  the 
curves  seen  in  Figure  40  are  copies  of  diagrams  produced 
automatically,  during  the  tests  of  two  pieces  of  bronze  from 
an  old  gun.  The  diagram  A  was  given  by  a  test  piece 
taken  from  the  exterior  of  the  gun,  where  it  had  been  little, 
if  at  all,  affected  by  the  compression  ;  and  that  marked  B  was 
given  by  a  specimen  taken  from  the  inside  of  the  bore,  where 
the  effect  of  compression  was  most  marked. 

On  comparison,  it  is  seen  that  the  effect  of  the  process  of 
35 


546  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

compression,  at  the  ordinary  temperature,  of  both  classes  of 
metal  is  the  same  in  kind.  So  far  as  it  affects  simply  the  re- 
lation of  the  distorting  force  to  the  distortion  produced  by  it 
in  each,  the  result  of  the  operation  is  the  elevation  of  the 
limit  of  cohesion  by  condensation  of  the  metal  and  by  the 
production  of  greater  homogeneity.  In  the  case  of  iron  and 
steel,  the  effect  of  this  treatment  is  heightened  by  the  pecu- 
liar property  of  those  metals  which  has  been  already  fully 
described.  With  both,  the  result  of  cold  working  is  highly 
advantageous  for  many  purposes.  In  some  cases — as,  for  ex- 
ample, when  the  metal  is  to  be  subjected  to  extremely  violent 
shocks,  and  is  therefore  likely  to  be  permanently  deformed, 
and  where  it  should  be  capable  of  offering  a  maximum  resili- 
ence up  to  the  point  of  actual  rupture,  e.g.t  the  armor-bolts 
of  an  iron-clad — the  metal  should  not  be  subjected  to  this 
process,  or  should  be  treated  very  cautiously.  Where  great 
strains  are  liable  to  be  met,  but  without  impact,  as  in  the  more 
usual  applications  of  such  metals  in  machinery,  and  as  in 
ordnance,  where  the  tremendous  p&ssures  exerted  are  due 
only  to  the  elasticity  of  a  confined  gas,  it  is  as  evident  that 
cold-worked  metals  are  well  fitted  to  give  a  maximum  resist- 
ance without  counterbalancing  disadvantages. 

304.  Historical— Discovery  of  Facts  and  Determination 
of  Laws. — It  is  impossible  to  say  just  when  all  the  facts  and 
laws  above  given  were  first  known.  The  first  intelligent 
statements  of  the  simpler  facts  were  made,  probably,  by 
Galileo,  who,  in  1656,  published  a  work — "  Opere  di  Galileo" 
— at  Bologna.  Robert  Hooke,  in  1676  and  1678,  was  the 
first  to  announce  the  important  principle  which  forms  the 
basis  of  our  theory  of  elasticity  of  bodies  within  the  elastic 
limit,  in  the  now  celebrated  Latin  phrase,  ut  tensio  sic  vts — 
the  extension  is  proportional  to  the  force.  Marriotte,  Leib- 
nitz, Parent,  Bernouilli,  and  other  mathematicians,  discussed 
the  theories  of  flexure  and  of  rupture  of  beams  with  equal 
mathematical  skill  and  practical  ignorance.  Coulomb,  about 
a  century  ago,  gave  the  best  mathematical  treatment  pub- 
lished up  to  that  time,  and  made  some  experiments  which 
were  of  real  value.  Dr.  Thomas  Young,  the  ablest  writer 


MECHANICAL   TREATMENT  OF  THE  METALS.          $4? 

u  is  ever  devoted  a  mind  rich  alike  in  scientific  knowledge 
h.  power  of  useful  application,  to  practically  valuable 
study,  defined  the  modulus,  or  coefficient,  of  elasticity,  and 
reduced  to  practical  shape  the  laws  enunciated  by  Hooke 
and  other  earlier  writers.  Dr.  Young  also  defined  the  quality 
which  Professor  Lewis  Gordon  afterward  called, "  resilience," 
and  showed  that  it  measured  the  amount  of  "  work  "  done  in 
distorting  a  body.* 

The  first  connected  and  special  treatise  on  strength  of 
materials,  and  on  construction,  was  the  work  of  the  dis- 
tinguished Navier,  the  lecturer  at  the  £cole  des  Fonts  et  Chans- 
stes,  in  1824 ;  but  Tredgold  had  already  prepared  his  excellent 
treatise  on  iron.  Since  then,  Fairbairn  and  Hodgkinson, 
Morin,  and  many  others,  have  written  valuable  treatises  on 
the  subject,  or  upon  special  divisions. 

Probably  the  most  reliable  and  extended  of  early  re- 
searches in  this  field  were  the  experimental  investigations  of 
Muschenbroek,  of  which  an  account  is  given  in  his  Introduc- 
tion to  Natural  Philosophy,  published  in  1762.  Banks,  in 
1803,  and  Rondelet,  in  his  "Art  de  Batir"  1814,  published 
the  results  of  experiments  on  iron.  The  best  work  which  has 
since  been  done  has  been  published  within  a  few  years  by 
Fairbairn  and  Hodgkinson,  Kirkaldy,  Styffe,  Bauschinger, 
Wohler,  and  by  our  own  countrymen,  Rodman,  Wade, 
Shock  and  some  other  experimenters  in  special  directions. 

The  fact  of  the  existence  of  an  elastic  limit  was  very  early 
discovered.  Duleau,  in  his  u  Essai  Thtorique  et  Experimental 
sur  la  Resistance  du  Per  Forgt"  printed  in  1820,  gives  the 
elastic  limit  of  that  metal  as  at  8,540  pounds  per  square  inch, 
and  at  an  extension  of  about  1-3333  °f  tne  original  length  of 
the  piece  in  tension.  Tredgold,  writing  in  1823,  says:  UI 
find  that  while  the  elastic  force,  or  power  of  restoration, 
remains  perfect,  the  extension  is  always  directly  propor- 
tional to  the  extending  force,  and  that  the  deflection 
does  not  increase  after  the  load  has  been  on  for  a  second  or 
two ;  but  when  the  strain  exceeds  the  elastic  force,  the  ex- 
tension or  deflection  becomes  irregular  and  increases  with 

*  Thomson  and  Tait;  Nat.  Philos  ,  vol.  i.,  part  ii.,  p.  228. 


548  MATERIALS  OF  ENGINEERING—NON-FERROUS  METALS. 

time."  Coulomb  had  already,  many  years  before,  noticed 
that  many  materials  take  a  permanent  set  long  before  the 
breaking  point  is  reached,  and  Emerson  had,  as  early  as  1758, 
asserted  that  the  materials  of  construction  should  not  be  sub- 
jected to  a  force  exceeding  from  one-third  to  one-half  their 
ultimate  resistance,  and  thus  proposed  the  now  invariable 
practice  among  intelligent  engineers  of  taking  a  certain 
"  factor  of  safety."  In  Tredgold's  time,  also,  the  work  of 
Telford,  Brown,  Rennie,  Barlow,  and  Rondelet,  was  well 
known.  The  fact  that  the  elastic  limit  of  a  piece  of  metal 
exceeds  its  primitive  value  more  and  more  as  the  piece  is 
more  and  more  distorted,  was  exhibited  by  some  of  the  very 
earliest  of  these  experiments.  Dr.  Young,  in  1807,  made  the 
fact  the  basis  of  his  remark:  "A  permanent  alteration  of 
form  limits  the  strength  of  materials  with  regard  to  practical 
purposes,  almost  as  much  as  fracture ;  since,  in  general,  the 
force  which  is  capable  of  producing  this  effect  is  sufficient, 
with  a  small  addition,  to  increase  it  till  fracture  takes  place." 
(Nat.  Phil.,  vol.  i.,  p.  141.)  He  also  pointed  out  the  impor- 
tance of  the  determination  of  the  resilience  of  a  piece  as  a 
measure  of  its  power  of  resisting  impact.  Tredgold  gives, 
1823,  simple  rules  for  the  application  of  this  principle,  and 
both  indicate  the  necessity  of  noting  the  variation  of  the  re- 
sistance as  distortion  progresses  in  order  to  obtain  a  measure 
of  that  resilience. 

305.  Experiments  published  in  1840,  in  the  Phil.  Trans- 
actions, by  Hodgkinson,  were  the  first  to  supply  data  for  an 
exact  determination  of  the  method  of  variation,  and  of  the 
values  of  the  normal  elastic  limit  from  the  instant  of  its  de- 
parture from  its  primitive  value.  His  work  is  still  quoted  as 
standard  authority,  and  as  the  most  extended  as  well  as 
thoroughly  precise  series  of  experiments  yet  made.  His 
later  work,  extending  over  several  years,  is  no  less  valuable. 
His  tabulated  results  of  test  showed  that  sets  occur  with  very 
light,  if  not  under  all,  loads ;  that  the  sudden  change  which 
marks  what  is  here  termed  the  apparent  elastic  limit,  is 
followed  by  a  gradual  elevation  of  the  limit  as  distortion 
proceeds,  and  that  the  normal  elastic  limit  has  a  value,  for 


MECHANICAL   TREATMENT  OF  THE  METALS.          $49 

each  stage  of  distortion,  which  may  be  expressed  by  formulas 
of  the  kind  already  given.  The  fact  was  shown  that  the  in- 
crease of  resistance,  as  change  of  form  occurred,  became  less 
and  less  marked  up  to  the  maximum. 

Clark,  in  his  account  of  the  Britannia  and  Conway  bridges, 
in  1850,  makes  the  statement,  based  on  results  obtained  by 
Hodgkinson  and  himself:  "  We  have  seen  that  as  we  increase 
the  permanent  set  of  wrought  iron  we  diminish  the  subse- 
quent extension  and  compression  from  any  load,  and  we 
have  alluded  to  the  fact  that  the  tubes  would  have  deflected 
less  from  any  given  load  if  the  top  and  bottom  had  been 
previously  compressed  and  extended  by  any  artificial  strain. 
It  follows  from  this  consideration  that  if  the  compressed  and 
extended  portion  of  a  wrought  iron  bar  could  be,  by  any 
artificial  means,  permanently  strained  previously  to  its  em- 
ployment as  a  beam,  such  a  beam  would  deflect  less  than  a 
new  bar,  and  would  be  practically  a  stronger  beam,  since  the 
strength  is  regulated  solely  by  the  bending  of  the  bar."  This 
is  probably  the  first  time  that  such  a  statement  was  made  of 
this  now  well-known  and  very  important  principle.  Long 
after,  few  engineers  were  aware  of  the  fact  that  it  was  then 
so  distinctly  enunciated  and  that  the  discoverer  determined, 
by  direct  experiment,  the  effect  of  this  method  of  treatment. 

Clark  gives  the  tabulated  results  of  test  of  bars  thus 
treated,  beside  those  derived  from  the  test  of  other  bars  left 
in  their  original  state.  The  former  deflected  but  1.765  inches 
under  a  load  of  46.5  hundredweight;  while  the  latter  de- 
flected 5.145  inches  under  a  load  of  41.9.  The  bars  were  \y2 
inches  square  and  the  supports  were  3  feet  apart. 

Werder,  at  Munich,  in  1854,  used  tie-rods  which,  by  a  single 
effort  of  tension,  had  been  similarly  stiffened.  Neither 
Clark  nor  Werder  seems  to  have  understood  the  peculiar 
phenomenon  of  the  exaltation  of  the  normal  elastic  limit  by 
intermitted  strain,  or  to  have  availed  himself  of  it  by  re- 
peating the  efforts  of  distortion. 

Later  experiments  made  at  the  Woolwich  dockyard  ex- 
hibited another  interesting  and  important  phenomenon  due 
to  the  same  characteristic.  A  rod  was  broken  several  times 


55O  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

in  succession,  and  exhibited  continually  increasing  ultimate 
resistance.  Other  rods  similarly  treated  gave  the  same  re- 
sult. The  mean  of  10  gave  a  tenacity  at  the  first  fracture  of 
24.04  tons  per  square  inch  ;  the  means  of  succeeding  breaks 
were  at  25.94,  27.06,  29.20,  while  the  extension  varied  too 
irregularly  to  indicate  any  law.  Similar  experiments  have 
since  been  made  in  1873,  by  Bauschinger  and  other  experi- 
menters. It  was  at  first  generally  supposed  that  the  last 
noted  behavior  of  iron  was  due  to  the  obvious  fact  that  the 
bar  must  have  broken  at  the  weakest  point  first,  at  the  next 
weakest  place  next,  and  so  on,  until  the  last  fracture  occurred 
at  very  nearly  the  section  of  maximum  strength  of  the  bar. 
It  is  now,  however,  evident  that  it  is,  or  may  be,  due  partly 
to  the  action  noted  by  Clark,  and  also  that  it  may  take  place 
in  metals  of  both  the  classes  which  have  been  above  defined 
by  the  writer.  In  the  iron  class,  however,  the  effect  is  un- 
doubtedly more  marked  than  in  metals  of  the  tin  class,  since 
there  the  exaltation  of  the  normal  elastic  limit  also  comes  in 
to  increase  the  resisting  power. 

306.  The  Exaltation  of  the  Normal  Series  of  Elastic 
Limits  by  intermittence  of  strain  and  by  lapse  of  time  at  a 
constant  distortion,  was  observed  by  the  Author  in  1873. 
Commander  L.  A.  Beardslee,  U.  S.  N.,  independently  noted 
the  same  phenomenon,  later  in  the  same  year.  The  latter 
has  since  determined  the  magnitude  of  this  change  in  iron 
during  periods  varying  from  one  second  to  one  year.  (See 
Part  II.,  Art.  298.)  The  Author,  at  about  the  same  time,  ob- 
served the  depression  of  the  normal  series  of  elastic  limits 
in  the  inelastic  metals. 

As  early  as  1858,  Prof.  James  Thomson,  who  had  seen  the 
importance  of  the  property  which  produced  the  variation  of 
resistance  of  materials  between  their  primitive  elastic  limits 
and  their  ultimate  fracture,  and  had  called  it  "viscosity,"  had 
shown  its  effect  in  modifying  the  mathematical  expressions 
deduced  for  the  torsional  resisting  power  of  metals.  He 
pointed  out  the  marked  difference  in  the  forms  of  these 
formulas  where  applicable  to  brittle  and  to  ductile,  or  viscous 
metals,  and,  in  the  latter  case,  to  the  resistance  within  and 


MECHANICAL  TREATMENT  OF  THE  METALS.          551 

beyond  the  primitive  elastic  limit.  Almost  nothing  has, 
however,  been  since  done  in  the  further  modification  of  work- 
ing formulas  with  reference  to  the  position  and  variation  of 
the  normal  elastic  limit,  or  to  the  determination  of  actual 
resistance,  except  that  the  Author  has  applied  the  same  proc- 
ess to  the  modification  of  formulas  for  transverse  resistance  of 
tough  metals,  and  independently  of  Prof.  Thomson,  but  many 
years  later,  to  the  general  case  of  torsion  and  to  the  inter- 
mediate condition  in  which  a  part  only  of  the  section  is 
strained  beyond  the  primitive  elastic  limit. 

M.  Tresca  and  Captain  Beardslee  have  shown,  as  has  the 
Author  (1873-83),  all  working  independently,  that,  with  iron, 
the  variation  of  the  normal  elastic  limits  may  extend  nearly 
or  quite  up  to  the  point  of  actual  rupture,  and  that  the  mod- 
ulus of  elasticity  remains  almost  unchanged.  The  Author, 
experimenting  with  all  the  common  materials  of  construction 
and  with  the  whole  range  of  alloys  of  copper-tin  and  copper- 
zinc  and  with  the  copper-tin-zinc  alloys,  has  found  the  same 
to  be  true. 

Fairbairn,  who  was  thoroughly  familiar  with  the  behavior 
of  iron  under  strain,  supposed  the  increase  of  resistance  with 
distortion  to  be  a  consequence  of  the  gradual  bringing  into 
action  of  particles  in  bodies  which  are  not  homogeneous  as 
to  strain,  as  the  fibres  of  a  rope  are  brought  gradually  into 
tension  as  the  rope  is  more  and  more  stretched.  The  Author 
has  proposed  a  very  similar  explanation  of  the  exaltation  of 
the  normal  elastic  limit  by  intermitted  strain,  and  has  shown 
how  such  a  condition  may  be  produced  by  the  process  of 
manufacture  of  those  metals  which  exhibit  that  phenomenon 
most  strikingly,  but  does  not  regard  it  as  a  satisfactory  ex- 
planation of  the  kind  of  variation  of  the  elastic  limit  which  is 
observed  in  both  classes  of  metals  alike,  to  explain  which  it 
was  offered  by  Fairbairn. 

Kick  has  (1870-80)  shown  the  increased  resistance  of  soft 
bodies  attacked  by  shock,  and  confirms  the  deductions  of  the 
Author  in  that  respect. 

307.  Strain-Diagrams. — Gen.  Morin  was  probably  the 
first,  about  1850,  to  represent  the  relation  of  the  distorting 


552  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

force  to  the  amount  of  distortion  by  the  graphical  method, 
and,  in  his  "Resistance  des'Materiaux"  plotted  beautifully  the 
results  of  Hodgkinson's  experiments.  His  curves  exhibit 
perfectly  the  characteristics  of  the  metals,  the  tests  of  which 
they  represent,  and  exhibit  plainly  and  accurately  the 
variation  of  the  elastic  limit  by  continued  strain.  They 
do  not,  of  course,  indicate  the  exaltation  of  the  normal  limit 
by  intermitted  strain.  Mallet,  in  1856,  uses  the  same  curves 
to  illustrate  his  application  of  the  principle  of  the  equivalence 
of  the  work  done  in  producing  fracture  of  the  materials  used 
in  the  construction  of  ordnance  with  the  resilience  of  the 
metal,  and  the  vis  viva  of  the  shot  or  other  mass  attacking  by 
impact.  Gen.  Rodman,  Major  Wade,  Kirkaldy,  Styffe,  and 
other  later  experimenters,  have  used  the  graphical  method 
during  the  last  quarter  of  a  century  in  illustrating  nearly  all 
their  work.  In  all  such  strain-diagrams,  the  variation  of 
the  elastic  limit  is  exhibited,  and  the  law  of  its  variation 
with  gradual  change  of  form  is  expressed.  Rodman  was  the 
first  investigator  to  adopt  the  method  as  a  system,  using  it  in 
his  report  on  his  experiments  on  metals  for  cannon  made  in 
1856  and  1857. 

Finally,  the  Author,  in  1873,  observed  the  exaltation  of 
the  normal  series  of  elastic  limits  as  recorded  on  automatic- 
ally produced  strain-diagrams,  and  gave  an  account  of  that, 
and  of  other  interesting  phenomena  exhibited  by  the  auto- 
graphic strain-diagram, 

308.  History  of  Processes  of  Working  Metals.-— Re- 
verting to  the  several  processes  of  working  metals  which  have 
been  described,  it  will  be  seen  that  the  methods  of  securing 
improvement  by  an  increase  of  homogeneousness  by  treat- 
ment of  the  metal  ^hile  fused,  have  no  relation  to  any  other 
modification  of  the  elastic  limit  than  that  which  distinguishes 
a  structurally  weak  and  defective  material  from  a  more  per- 
fect specimen  of  the  same  metal.  The  processes  of  cold-roll- 
ing and  of  other  methods  of  compression  of  cold  metal  in- 
volve, whether  the  metal  be  iron,  steel,  bronze  or  brass,  that 
form  of  variation  of  the  elastic  limit  which  has  been  known 
since  the  time  of  Tredgold,  and  possibly  of  Muschenbroek, 


MECHANICAL  TREATMENT  OF  THE  METALS.          $53 


in  addition  to  the  change  produced  by  the  condensation  of 
solidifying  metal,  and  in  a  marked  degree.  The  ordinary 
processes  of  working  metal  hot  are  intermediate  in  character 
between  the  other  two.  It  is  seen  that  the  iron  class,  whether 
worked  hot  or  cold,  experiences,  besides,  a  change  which  the 
writer  has  proposed  to  denominate  the  "  exaltation  of  the 
normal  elastic  limit  by  intermitted  strain."  It  is  seen  that 
the  latter  action  is  not  involved  in  the  cold-working  of 
bronze. 


lntem»ay  Cooled  Inrot 


FIG.  41. — INGOTS. 


In  securing  homogeneousness  of  structure  by  treatment  of 
the  molten  metal,  various  methods  of  fluxing  have  been  prac- 
tised from  an  unknown  and  very  early  period.  The  most  suc- 
cessful methods  have  involved  the  use  of  phosphorus  as  a 
flux  in  casting  bronze  and  of  the  silicide  of  iron  and  man- 
ganese for  iron  and  steel.  The  method  of  compression  of 
molten  metal  at  the  point  of  solidification  was  first  brought 
into  use  by  Sir  Joseph  Whitworth,  of  Manchester,  England, 
about  1860.  It  was  subsequently  adopted  on  the  Continent 
of  Europe,  and  is  now  becoming  well  recognized  as  one  of 
the  most  efficient  known  methods  of  producing  metal  of  the 
highest  possible  grade.  This  method  was  first  applied  to  the 


5 54  -MA TERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 

production  of  bronze  guns  by  Colonel  Lavroff,  in  the  Russian 
arsenals,  about  1867.  By  him  the  process  was  perfected  in 
1870. 

Chill-cast  bronze  was  probably  first  proposed  by  Mallet  in 
1856,  and  he  at  the  same  time  proposed  the  use  of  a  hollow 
core  to  be  cooled  by  currents  of  air,  as  in  Figure  41.  This 
method  was  adopted  with  great  success  by  makers  of  bronze 
a  few  years  later.  It  was  adopted  by  General  Uchatius  in  1 873, 
after  having  seen  the  remarkable  success  of  M.  Lavissiere, 
who  exhibited  a  bronze  gun  made  in  this  way  at  the  Vienna 
Exhibition  of  that  year.  Colonel  Rosset,  of  the  Italian  artil- 
lery, had  also  adopted  the  same  method,  and  it  is  referred  to 
in  his  work,  "  Esperienze  Meccaniche  sulla  Resist enza  del  Prin- 
cipali  Met  alii  da  Bocche  da  Fuoco.  Torino,  1874,"  in  which 
he  also  recommends  the  adoption  of  the  Dean  method  of 
making  bronze  guns. 

The  form  of  chill  used  for  ordnance  is  shown  on  a  subse- 
quent page. 

The  ordinary  methods  of  forging  and  working  metals  at  a 
red  heat  were  introduced  hundreds  of  years  ago,  and  their 
early  history  is  quite  unknown.  Rolling  mills  for  working 
iron  were  introduced  about  1784  by  Cort,  the  inventor  of  the 
process  of  puddling. 

Wire  was  made  by  hammering  by  the  ancients  and  at  a 
date  which  is  not  known.  Wire  drawing  was  invented  500 
years  ago,  in  Nuremberg,  Bavaria,  by  a  "  wire-smith  "  named 
Ludolf.  By  the  middle  of  the  seventeenth  century  the  busi- 
ness of  wire  drawing  had  been  imported  into  Great  Britain, 
and  was  employing  thousands  of  people  in  England  and  in 
Germany.  In  1813  Dr.  Wollaston  introduced  his  method 
of  enclosing  one  metal  within  a  bar  of  another  metal  and 
drawing  down  the  two  together.  When  finished  the  outer 
coating  was  dissolved  off  by  an  acid,  and  the  inner  and  ex- 
tremely fine  wire  was  left  perfect.  Platinum  wire  has  been 
thus  made,  by  enclosing  it  in  silver,  of  but  i-3O,oooth  inch 
diameter.  Mr.  Brockedon,  as  early  as  1819,  using  the  pre- 
cious stones  as  draw-plates,  produced  wire  0.0033  mcn  m 
diameter. 


MECHANICAL  TREATMENT  OF  THE  METALS.          555 

309.  Cold-working  Iron,  as  a  system,  has  been  prac- 
tised but  a  comparatively  short  time.  It  had  long  been 
known  that  such  treatment  imparted  stiffness  and  elasticity 
to  metals,  but  it  was  not  known  at  what  stage  of  the  process 
of  condensation,  if  any,  the  action  ceased  to  produce  benefit 
and  became  liable  to  injure  the  metal  by  weakening  it  by  the 
introduction  of  internal  strains.  It  was  well  known  to  ex- 
perienced engineers  and  metal  workers  that  cold-hammered 
iron,  and  iron  rolled  cold,  was  often  seriously  injured  by  being 
worked  too  cold  ;  and  the  Author  was  accustomed,  many 
years  ago,  to  give  special  instructions  to  the  smith  who  was 
about  to  make  the  forgings  of  a  steam  engine  which  were 
to  be  left  without  tool  finish,  not  to  attempt  to  give  them  the 
fine  finish  under  the  hammer  which  may  be  given  by  hammer- 
ing at  a  "  black  heat,"  lest  they  should  be  weakened  by  the 
treatment.  It  was  not  then  generally  known  that  cold-work- 
ing might  be  so  conducted,  and  safely,  as  to  secure  an  in- 
crease of  strength. 

The  process  of  cold-rolling  was  introduced  in  the  United 
States  by  its  inventor,  Bernard  Lauth.  His  experiments  were 
first  made  in  1854,  and  in  1857  he  fitted  up  a  set  of  rolls  for 
systematic  experiment  ;  and  in  January,  1858,  he  brought  out 
cold-rolled  iron  as  an  article  of  manufacture.  Two  other  in- 
ventors, Messrs.  Cuddy  and  Savory,  invented  very  similar 
processes  almost  simultaneously  with  their  successful  rival 
Lauth.  Mr.  Lauth  was  assisted  pecuniarily,  and  by  the  prac- 
tical knowledge  of,  Mr.  B.  F.  Jones,  and  the  work  was  done  at 
the  mills  of  the  American  Iron  Works,  Pittsburgh.  The  proc- 
ess was  introduced  into  Great  Britain  by  Lauth  in  1858.  He 
introduced  it  into  France  and  Belgium  in  the  following  year. 
The  process  has  now  become  one  of  the  well-established 
methods  of  iron-working,  and  is  gradually  becoming  recog- 
nized as  a  valuable  method  of  modifying  the  properties  of 
steel,  bronze,  and  other  metals. 

As  applied  to  iron  and  steel,  it  evidently  results  in  the 
strengthening  of  the  metal  by  condensation  and  by  the  pro- 
duction of  greater  homogeneousness  of  structure,  and  also 
gives  stiffness  and  elasticity  by  the  long-known  form  of  ele- 


556  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS. 


vation  of  the  primitive  elastic  limit,  as  well  as  by  the  exalta- 
tion of  the  normal  limit  by  the  action  ascribed  by  the  Author 
to  intermitted  strain.  As  applied  to  gun-bronze  and  other 
metals  of  the  tin  class,  it  produces  its  useful  effect  only  by 
the  first  two  methods  of  change. 

310.  Cold-working  Bronze  and  that  class  of  metals  by 
Mr.  Samuel  Buel  Dean,  of  Boston,  Mass.,  was  applied  by  him 
to  the  improvement  of  gun-bronze  at  some  time  previous  to 
1859,  at  which  date  he  laid  his  plan  before  the  ordnance 
officers  of  the  United  States  War  Department, 
and  illustrated  its  effects  by  treating  samples  of 
gun  metal,  as  has  already  been  described.  The 
Ordnance  Bureau  ordered  guns  to  be  made  by 
the  Dean  method  in  July,  1870,  and  the  work 
was  subsequently  interrupted  in  consequence  of 
the  neglect  of  Congress  to  vote  the  necessary 
funds.  In  Great  Britain,  the  Committee  on  Field 
Artillery  for  India,  in  1870,  reported  in  favor  of 
the  adoption  of  this  method. 

General  Uchatius,  of  the  Austrian  artillery, 
adopted  the  process  in  1873,  using  the  method 
of  condensation  described  in  the  patent  of  the 
inventor,  Dean,  which  had  been  filed  in  Vienna 
July  1 6,  1869,  in  Register  sub-vol.  xix.,  fol.  378. 
The  British  and  French  patents  were  dated  May 
10  and  May  12,  respectively,  of  the  same  year. 
The  United  States  patent  was  dated  May  18. 
FIG.  42.— CHILL  Uchatius  adopted  the  method  of  chill-cast- 
FOR  ORDNANCE.  ing  SUggested  by  Mallet  in  his  work  "  On  the 
Construction  of  Artillery,"  as  has  already  been  stated.  The 
first  information  given  abroad  relating  to  the  Dean  process 
was  probably  the  statement  made  by  Mr.  Clemens  Herschel 
to  Mr.  Isidor  Kanitz,  of  Vienna,  May  18,  1869. 

The  following  figure  represents  Dean's  apparatus.  The 
metal  cylinder  to  be  strengthened,  A,  is  supported  by  a  cast- 
ing, B,  while  the  rod,  C,  carrying  the  mandrel,  is  driven 
through  it. 

The   adoption  of  the  process  invented  by  Dean,  by  the 


MECHANICAL  TREATMENT  OF  THE  METALS.          557 

Italian  military  authorities,  was  advised  by  Colonel  Rosset 

also,    and  is  referred    to    in   his   work   on  gun 

metals,  published    almost   simultaneously  with 

the   description,    by  General    Uchatius,  of  the 

details   of   the    method    of  application   of   the 

Dean  process  in  the  Austrian  arsenal. 

311.  Conclusions. — The  processes  which 
have  been  described  at  such  length  in  the  pre- 
ceding pages  are  regarded  as  the  most  important 
known  processes  of  modification  of  the  primary 

\-^'  t  ^i  c    1  FlG.  43. — COLD- 

qualities  of  the  useful  metals.  WORKING 

It  may  be    concluded,   from  what  has  pre-      BRONZE. 
ceded,  that  the   proper   method   of   preparation  of  metal  to 
secure  a  maximum  value  is  the  following: 

(i.)  Reduce  the  metal,  when  possible,  to  the  molten  con- 
dition, flux  thoroughly  with  such  a  flux  as  will  remove,  first, 
all  deleterious  substances  with  which  the  metal  may  be  con- 
taminated ;  secondly,  every  particle  of  gaseous  oxygen  and 
of  oxide ;  and,  thirdly,  all  other  occluded  gas  liable  to  pro- 
duce "blow-holes." 

(2.)  Cast  the  metal  under  heavy  pressure,  in  order  to 
secure  maximum  density  and  to  close  up  every  pore  as  per- 
fectly as  possible.  If  the  metal  is  an  alloy  which  is  liable  to 
liquation,  it  should  be  cast  in  a  chill  of  sound  iron  and  of 
considerable  thickness. 

(3.)  If  the  metal  is  either  iron  or  steel,  produce  any  con- 
siderable change  of  shape  which  may  be  desired  by  rolling, 
by  the  drop-press,  or  by  hydraulic  forging  at  a  full  red  heat, 
and  permit  it  to  remain  unused  as  long  as  is  possible,  in  order 
that  the  internal  strain,  unavoidable  to  some  extent  with  any 
method  of  treatment,  may  be  given  time  to  become  reduced 
by  that  process  of  flow  which  will  ultimately  relieve  it.  If 
stiffness  and  a  more  perfect  elasticity  are  demanded,  finish 
by  the  process  of  cold-working,  taking  great  care  not  to  carry 
it  so  far  as  to  seriously  injure  the  continuity  of  the  metal. 

(4.)  The  bronzes,  and  other  metals  of  the  inelastic  and 
viscous  class,  may  be  given  very  considerable  modification 
of  form  by  the  processes  of  working  cold.  The  same  precau- 


55$  MATERIALS  OF  ENGINEERING— NON-FERROUS  METALS 

tion  must  be  taken  to  avoid  destruction  of  continuity,  and 
thus,  by  the  production  of  incipient  fracture,  permanently 
and  seriously  injuring  it. 

By  observing  these  precautions,  the  maximum  value  of  the 
metal  for  constructive  purposes  may  be  attained.  Whitworth 
has  made  "  homogeneous  iron  "  castings  having  a  tenacity  of 
35  tons  per  square  inch  by  his  process,  and  the  Author  has 
made  brass  without  any  special  treatment,  either  by  fluxing, 
compression,  or  other  modifying  processes,  having  a  strength 
of  70,000  pounds  per  square  inch  (4,921  kgs.  per  sq.  cm.)  It 
is  not  unlikely  that  the  theoretical  maximum  for  any  material 
— the  maximum  due  to  the  effort  of  the  force  of  cohesion, 
and  that  which  is  perhaps  approached,  in  special  cases,  in 
fine  wire — may  be  nearly  attained,  even  in  large  masses,  by 
the  skilful  and  intelligent  combination  of  the  processes  which 
have  been  here  described  in  the  treatment  of  such  cast  metals, 
and  in  their  adaptation  to  purposes  of  construction. 


INDEX. 


ART.  PACK 

Alloys 28  39 

aluminium 99,  100  178,  180 

[See  Antimony.] 

Babbitt's  anti-friction ' 139  215 

[See  Bismuth,  Brass.] 

Britannia  metal 126  202 

cadmium  and  copper 107  186 

characteristics 60  102 

chemical  natures 61  104 

classified  lists 142,  143  226 

composition,  special  standard 141  218-222 

conductivity,  electric 68  120 

thermal 67  118 

[See  Copper.] 

crystallization 69  123 

effect  of  small  doses  of  metal 135  212 

electric  conductivities 68  120 

expansions  by  heat 60         ,  116 

ferrous  copper 196  319 

fusible 117  193 

fusibility 63  1 10 

German  silver 102,138  182,215 

gravities,  specific 62  108 

grey  ternary 265  450 

heat  conductivities 67  1 18 

expansions 66  116 

specific 65  1 16 

investigations,  early 266  451 

indium  and  platinum 128  203 

iron,  copper  and  tin 96  174 

zinc 95  174 

and  tin... 113  189 

iron  and  manganese 127  203 

[See  Kalchoids,  Chap.  VI.,  Lead.] 

liquation 64  113 

lists,  classified 143  226 

manganese  bronze 97,  98,  194.  195     175.  i?6,  3^,  3*7 

andiron 127  203 

maximum 258-263  440-447 

mechanical  properties 71  126 

nickel  and  copper 101  181 

and  zinc IO2  182 

oxidation 70  124 

pewter 120  202 

platinum  and  indium 128  203 


56o 


INDEX. 


ART.  PAGE 

Alloys,  preparation 134  210 

phosphor  bronze 192,  193  312-314 

properties  [See  Chap.  III.]. 

recipes,  special 142  221 

[See  Resistances.] 

Spence's  metal 129  204 

specific  gravities 62  108 

heats 65  116 

silicon  and  copper 109,  no          187,  188 

solders 140  276 

special  recipes 142  222 

standard  compositions 141  218 

sterro-metals 220  368 

[See  Strength,  Tin.] 

thermal  conductivity 67  1 18 

uses 93  172 

[See  Zinc.] 

Thurston's  maximum j 258-262  440-447 

Aluminium 51,  185             88,  565 

bronze 99  176 

uses loo  180 

Analyses 27  39 

and  mixtures  of  copper-zinc  alloys 227  376 

Ancient  knowledge  of  metals I  3 

Anderson's  experiments  with  gun-bronze 188  308 

Annealing 293  526 

and  tempering,  effect  on  density 276  484 

tenacity 277  487 

Anti-friction  metal,  Babbitt's 139  215 

Antimony 47  82 

bismuth  and  lead 122  202 

tin 112  188 

and  zinc 125  202 

and  copper 104  185 

and  lead 1 18  196 

and  tin 123  202 

tin  and  zinc 124  202 

Appearance  of  brass,  test-pieces 224  371 

fractures 225  373 

bronze  test-pieces,  external 201  325 

fractures 203  330 

Arsenic  in  alloys 55  95 

Art  castings  in  bronze 136  212 

Babbitt's  anti-friction  metal 139  215 

Bar  copper 36  59 

Behavior  of  bronzes  under  test 202  326 

[See  Mechanical  Treatment,  Resistances.] 

Bell-metal 189  308 

Bischoff's  tests. . 185  303 

Bismuth  alloys 116  190 

antimony,  tin,  and  lead 125  202 

bronze 106  187 

and  copper 105  186 

fusible  alloys 117  193 

lead  and  tin 117  193 

ores 48  83 

Brass  [See  Chap.  V.,  X.]. 


INDEX. 

ART.  PAGE 

Brass,  alloys  tested  223  370 

analysis  of  mixtures 227  376 

appearances  of  fractures 225  373 

appearances  of  test  pieces 224  371 

application  in  arts 87,  90          159,  167 

[See  Bronzes.] 

casting,  temperatures 226  375 

classification,  Mallett's 86  159 

comparison  of  ductilities , 244  412 

elastic  limits 241  409 

moduli 242  411 

resiliences 240  409 

resistances 239  406 

specific  gravities 243  412 

compressive  resistance 232  385 

conclusions 245  413 

from  tests 239,  245          379,  413 

compositions 85,  227  158,  376 

definitions 84,  210          158,  366 

ductilities  [See  Resistances,  below] 244  412 

elastic  limits 241  409 

moduli 221  368 

experiments,  early 219  367 

fractures,  appearances 225  373 

foundry I Jl  207 

[See  Kalchoids,  Chap.  VI.] 

Mallett's  classification   86  159 

mixtures  and  analyses 85,  227          158,  376 

moduli  compared    242  41 1 

of  elasticity 221  368 

Muntz  metal 88  160 

notes  on  tests 230  383 

properties 92  165 

special 89  161 

records  of  tests 236  393 

resiliences  compared 240  409 

resistances  compared . 239  406 

compressive 232  385 

results  of  tests 228  378 

shafts 235  392 

tensile 231,  237          384,  404 

torsional 234  391 

transverse 233,  238          387,  406 

results  of  tests 228  378 

shaft  resistance 235  392 

special  properties 89  161 

specific  gravities  compared 243  412 

Britannia  metal 126  202 

Bronze  [See  Chaps.  IV.,  VI.,  IX.]. 

abrasive  resistance  of  phosphor-bronze 193  314 

alloys 72,  74,  *97    13°,  134, 320 

tested 199  322 

aluminium 99  178 

uses ioo  180 

Anderson's  experiments  on  gun-bronze 188  308 

appearance,  external,  of  test  pieces 201  325 

fractures 203  330 

behavior  under  test 202  326 

36 


52  INDEX. 

ART.  PAGE 

Bronze,  bell-metal,  Mallett's  experiments 189  308 

bismuth 106  187 

f  See  Brass.] 

casting,  temperature 200  324 

comparison  of  conductivities 216  363 

ductilities 225  361 

elastic  limits 213  358 

hardness , . .   217  363 

moduli  of  elasticity 214  361 

resistances 210  350 

resiliences 211  355 

specific  gravities 212  355 

compression  [See  Condensation,  below] 208  340 

resistance  of  ordnance-bronze 190  309 

conductivities,  comparative 216  "63 

condensation  [See  Compression,  above\. 

Dean  process.  ...*.... 297  530 

Uchatius' method 298  531 

experiments 299  538 

deductions 300  540 

[See  Copper.] 

Dean's  process  of  condensation 297  530 

denned 72,  186  30,  306 

density 79  141 

ductilities,  comparative 215  361 

early  compositions 77  139 

elastic  limits,  comparative 213  358 

elasticity  moduli,  compared 214  361 

ferrous  copper,  strength 196  319 

fractures,  appearances 203  330 

gravity,  specific 212  355 

gun  [See  Ordnance]. 

hardness,  comparative 217  363 

Riche's  experiments 191  312 

heat,  modifying  tenacity 270  477 

history 73  131 

impact  resistance  of  manganese-bronze 195  317 

[See  Kalchoids,  Chap.  VI.] 

manganese-bronze 97  175 

impact  resistance 195  317 

preparation 98  1 76 

strength 194  316 

maximum,  Thurston's 258  440 

metals  used  in  research 198  322 

moduli  of  elasticities,  compared 214  361 

oriental 78  140 

ordnance 80,  187    141,  306 

Anderson's  experiments 188  308 

[See  Compression  and  Condensation,  above.] 

Wade's  experiments 190  309 

phosphor-bronze 81  143 

abrasive  resistance 193  314 

tenacity 192  312 

uses 82  145 

preparation  of  manganese-bronze 98  176 

properties 75  136 

principal 76  137 

records  of  tests 204  335 


INDEX. 


563 


ART.  PAGE 

Bronze,  results  final 205  341 

resistances,  abrasive,  phosphor-bronze 193  314 

behavior  under  test 202  326 

compared 210,  218          346,  350 

l    *        c  -,  condensed  gun-bronze 190  309 

Uchatius'  experiments 299  538 

deductions.  300  540 

conductivities 216  363 

ductile 225  361 

elastic  limits 213  358 

moduli 214  361 

ferrous  copper 196  319 

hardness 217  363 

Riche's  experiments 191  311 

manganese-bronze 194  317 

impact 195  317 

phosphor-bronze,  abrasive 193  314 

tenacities 192  312 

tensile  strain-diagrams 206  374 

transverse  strain-diagrams 209  348 

silicon-bronze no  188 

specific  gravities 212  355 

strength  [See  Resistance]. 

stress  prolonged,  effect 281  497 

table 83  149 

temperature  of  castings 200  324 

tenacity  modified  by  heat 270  477 

tension,  strain  diagrams 206  344 

test  records 204  335 

test  pieces,  appearance 201  325 

behavior  under  test 202  326 

Thurston's  "  maximum  " 258-262  440—447 

[See  Tin.] 

transverse  strain-diagrams 209  348 

Uchatius'  experiments  in  compressed  bronze 299  538 

deductions.  300  540 

methods.. .  278  531 

uses  of  aluminium-bronze 100  180 

phosphor-bronze 182  145 

Wade's  experiments  on  gun-bronzes 197  320 

Bronzing 144  237 

Calcination  and  roasting 3  9 

Casting  in  bronze •. 136  212 

chill,  effect 275  483 

temperatures 200,  278          324,  488 

Characteristics  of  metals 22  30 

[See  Properties,  Resistances.] 

Chill-casting 275  483 

Chemical  analyses 227  376 

character  of  metals 27  39 

nature  of  alloys 61  104 

processes  in  metallurgy,  schedule 2  5 

Classification  of  brasses,  Mallett's 86  159 

useful  alloys 143  226 

Cold-rolling,  Lauth's  process 296  529 

tension,  "  Frigo  "-tension 301  540 


564  INDEX. 

ART.  PAGE 

Cold-working  metals 294  527 

bronze 310  556 

Dean's  process 297  530 

Uchatius'  experiments 298  531 

deductions 300  540 

iron 309  555 

Lavroff  s  process 290  523 

Commercial  copper 35  55 

lead 46  81 

metals,  prices   59  99 

rare 58  98 

tin 39  66 

Comparison  of  conductivity 216  363 

ductility 215  361 

elastic  limits 213         •  358 

hardness 217  363 

methods 302  540 

moduli  of  elasticity 214  361 

resiliences 211  353 

resistances 210  350 

specific  gravities 212  355 

Complex  copper  alloys 115  189 

Compression,  brass 232  385 

bronze '. 190  309 

strain-diagrams 208  346 

copper 171  278 

Dean's  process 297  530 

hardness 16,  217  20,  363 

Lavroff's  process 290  523 

[See  Ductility.] 

malleability 20  27 

non-ferrous  alloys 157  255 

[See  Tenacity.] 

Uchatius'  methods,  experiments,  deductions.  298-300  531-540 

Conclusions,  brasses  and  other  copper-zinc  alloys 229,  245          378,  417 

kalchoids  and  copper-tin-zinc  alloys 261  446 

mechanical  treatment 311  557 

Condensation  [&<?  Compression,  above\. 

Conductivity 17  21 

electric 17  21 

of  alloys 68  120 

bronzes 216  363 

thermal 17  21 

of  alloys , 67  118 

bronzes ; 216  363 

latent  heat 26  36 

Copper  and  antimony 104  185 

and  bismuth 105,  106          186,  187 

bar 36  59 

and  cadmium 107  186 

commercial 35  55 

tests 169  272 

complex  alloys 115  189 

compression 171  278 

by  impact 172  281 

distribution 29  42 

Dronier's  alloy  of 114  189 

elasticity,  modulus 174  286 


INDEX. 


565 


ART.  PAGB 

Copper  and  German  silver 102,  138  182,  215 

heat,  modifying  tenacity 269  47*) 

history 29  42 

impact,  compression  by 172  281 

and  iron 103  183 

and  tin  and  zinc 113  189 

and  iron  and  zinc 95  174 

[See  Kalchoids,  Chap.  VI.] 

lead 108  187 

and  tin in  188 

mercury 114  189 

modulus  of  elasticity 174  286 

and  nickel 101  l8l 

and  zinc 102  182 

properties 34  54 

qualities 30,  168,  174,  176     43,  271,-  286,  287 

resistance 167  270 

compressive 1 71  278 

to  impact 172  281 

elastic  modulus 174  286 

shearing 170  277 

tensile 167  276 

torsional 175  287 

transverse 173  284 

shearing,  resistance 170  277 

sheet 36  59 

and  silicon 109,110  187,188 

sterro-metal 247  415 

tenacity 167  270 

modified  by  heat 269  476 

tests  [See  Resistance,  above] 168  271 

commercial  copper 169  272 

mean  results 176  287 

torsional 175  287 

transverse 173  284 

and  tin  [See  Bronze]. 

and  zinc 94,  248  172,  416 

torsional  resistances 175  287 

transverse  tests 173  284 

and  zinc  [See  Brass]. 
Crystallization   23,  69  30,  125 

Dean  process  applied  to  bronze 297  530 

Deflection,  effect  of  stress 284  502 

[See  Resistance,  Transverse.] 

Density,  annealing  effects 276  484 

bronze 79  141 

[&e  Mechanical  Treatment.] 

Discussion  of  experiments  on  kalchoids 260  443 

Distribution  of  resistances 160  258 

Dronier's  alloy 1 14  189 

Ductilities 20  27 

[See  Annealing.] 

brasses,  compared 244  412 

bronzes,  compared 215  361 

hardness 16,  191,  217  20,  311.  363 

kalchoids  and  other  copper-tin-zinc  alloys. . .  '. .   256  434 

and  malleability  of  metals 20  .27 


566  INDEX. 

ART.  PAGE 

Ductilities   [See  Elastic  Limit,   Elasticity,   Mechanical   Treat- 
ment, Resistances,  Strain-diagrams]. 

Earlier  experiments 219  367 

investigations 266  451 

Early  bronzes . .  77  139 

Elastic  limits  of  brass  and  other  copper-zinc  alloys 241  409 

bronze  and  other  copper-tin  alloys 213  348 

effect  of  stress,  intermitted 285  508 

variable 286  512 

exaltation 306  550 

non-ferrous  metals 152  249 

Elasticity  [See  Annealing,  Ductility,  Mechanical  Treatment]. 

modified  by  heat 272  480 

moduli  for  brass  and  other  copper-zinc  alloys 221  368 

bronze  and  other  copper-tin  alloys 214  361 

copper 1 74  286 

tin 179  294 

[See  Resilience,  Resistance,  Shock.] 

non-ferrous  metals 153  251 

proportioning  for 155  255 

[See  Strain-diagrams.] 

Wertheim's  work 184  300 

Electric  conductivity 17  21 

of  alloys 68  120 

bronzes 216  363 

Engineer,  requirements 12  17 

Equations  of  resistance  curves 151  248 

Exaltation  of  elastic  limit .-.  306  550 

Expansion  by  heat 24,  66  34,  116 

Experiments  [See  Investigations]. 

Factors  of  safety 148  244 

Ferrous  copper,  strength 196  319 

Fluctuation  of  resistance 282  498 

Fluxes 5  12 

Forging,  drop 291  524 

hydraulic 292  525 

Formulas  for  transverse  loading 162  260 

Frigo  tension 301  540 

Fuels 6  13 

Furnace  manipulation 133  209 

Fusibility 25,  63  36,  no 

Fusible  alloys 117,  120          193,  198 

German  silver 102,  138          182,  215 

Grey  ternary  alloys 265  450 

Gun-bronze  [See  Bronze]. 

Hammering  and  rolling 303  543 

Hardness 1 6  20 

of  bronzes  and  other  copper-tin  alloys 191,  217          311,  363 

[See  Mechanical  Treatment.] 

Heat,  annealing  and  tempering,  effect  on  density 276  484 

tenacity 277  487 

conductivity 17  21 

of  alloys 67  118 

bronzes 216  363 


1XDEX.  567 

ART.  PAGE 

Heat,  effect  of  sudden  variations 274  482 

expansion  ....  25  34 

of  alloys 66  1 16 

fusibility 26  36 

of  alloys 63  no 

latent 26  "36 

modifications  of  elasticity 272  480 

stress 273  481 

tenacity  of  bronze 270  477 

copper 269  476 

various  metals 271  480 

specific 24  31 

of  alloys 65  116 

temperature  of  casting  of  brasses 226  375 

bronzes 220  324 

effect  on  strength 278  488 

thermo-tension. 293  526 

Historical  discoveries 304  546 

processes 308  550 

History  of  the  bronzes 73*  131 

copper 29  42 

experiments 305  548 

discovery  of  the  exaltation  of  elastic  limits 308  552 

strain-diagrams 307  551 

Hydraulic  forging 292  525 

Impact,  non-ferrous  metals 153  251 

proportioning  for 155  255 

[See  Resilience.] 

Improvements  in  ternary  alloys 257  437 

Investigations  [See  Metals  and  Alloys  in  detail]. 

Anderson's  experiments  with  gun-bronze 188  301 

Bischoff 's  method  of  test 185  303 

early,  in  the  zinc-tin  alloys 266  451 

Mallett's  experiments  with  bell-metal 189  308 

[See  Mechanical  Treatment.] 

Riche  on  hardness  of  bronze 191  311 

Thurston's  investigations,  transverse  resistance.  160  258 

torsional 166  269 

impact  on  copper  ...  172  281 

tenacity  of      "      ...  173  285 

gun-bronze 190  309 

copper-tin-alloys  . . .  197  320 

"      zinc    "     ....  222  369 

plan  of  investigations.  249  417 

model  of  ternary  alloys  252  427 

maximum  bronzes. . .  258  440 
principle    (effects    of 

time) 279  489 

experiments  on  ditto 

284-285     502-508 

U.  S.  Test  Board,  copper- tin  alloys 197  320 

copper-zinc  alloys 222  369 

copper-tin-zinc  alloys 248  416 

Wade's  experiments  with  gun-bronze 187  306 

Wertheim  on  elasticity  of  alloys 184  300 

Indium 56  96 

and  platinum 128  203 


568 


INDEX. 


ART.  PAGE 

Iron  and  copper 103,  196          183,  319 

and  tin 96  174 

and  zinc 113  189 

and  zinc 95  174 

and  manganese 127  203 

[See  Mechanical  Treatment.] 

Kalchoids  and  other  copper-tin-zinc  alloys  [See  Chap.  XI.]. 

Lacquering 145  239 

Latent  heat 26  36 

Lauth's  process  of  cold  rolling 296  529 

Lavroff  process  of  condensation 290  523 

Lead 43  77 

and  antimony 118  196 

and  bismuth 122  202 

tin 123  202 

and  bismuth 125  202 

bismuth  and  tin 117  193 

commercial 46  8 1 

and  copper 118  187 

and  tin in  188 

fusible  alloys 117,  120          193,  198 

galena  smelting 45  79 

ores 44  78 

and  tin 120  198 

Liquation 64  113 

Lustre  of  metals  and  alloys 18  24 

Magnesium 54  94 

Malleability  and  ductility 20  27 

Mallett's  classification  of  bronzes 86  159 

experiments  with  bell-metal 189  308 

Manganese 57  97 

bronze 97  175 

impact  resistance 195  317 

preparation 97  176 

and  iron 127  203 

"  Maximum  "  bronzes,  Thurston's 258  440 

Mechanical  processes 7  13 

properties  of  alloys 71  126 

[See  Metallurgy.] 

working  of  brass 91  163 

metals 8  14 

Mechanical  treatment  of  metals  and  alloys  [See  Chap.  XIV.]. 

cold-rolling,  Lauth's  process 296  529 

cold-working 294  527 

bronze 310  556 

iron 309  555 

comparison  of  methods 302  541 

conclusions 311  557 

condensation,  Dean's  process 297  530 

Uchatius'  method,  ex- 
periments, deduc- 
tions    298-300  53I-54O 

Dean  process  of  condensation 297  530 

discoveries 304  546 

drop-forging ^ .  292  525 


INDEX.  569 

ART.  PAGE 

Mechanical  treatment  ;  exaltation  of  elastic  limit 308  552 

forging 291  524 

drop 292  525 

hydraulic 292  525 

frigo-tension 301  540 

hammering 303  543 

historical 304  546 

history  of  experiments 305  548 

hydraulic  forging 292  525 

impact 172  281 

Lauth's  process  of  cold-rolling 296  529 

Lavroffs  process  of  condensation. . . .  290  523 

qualities  effected  by 288  517 

rolling 291,  303  524,  543 

strain-diagrams 307  551 

thermo-tension 293  526 

Uchatius'  method  of  condensation,  ex- 
periments, deductions 298-300          531-540 

working  of  metals 8  14 

brass 91  163 

wire-drawing 295  527 

Melting  and  casting 132  207 

Mercury 52  90 

and  copper,  Dronier's  metal 114  189 

Metallurgy,   calcination 3  9 

chemical  processes,  schedule 2  5 

copper  ore  reduction 32  47 

fluxes 5  12 

fuels 6  13 

galena  smelting 45  79 

[See  Ores.] 

roasting 3  9 

reduction  of  copper  ore 32  47 

tin  ore 38  64 

schedule  of  chemical  processes 2  5 

smelting 4  n 

galena 45  79 

zinc  ores 41  41 

tin  ore  reduction 38  64 

zinc  smelting 41  41 

Metals  [See  Index  in  detail]. 

ancient  knowledge I  3 

defined 9  16 

useful 10  ii 

various 183  298 

Moduli  of  brass  and  other  copper-zinc  alloys,  compared 242  411 

elasticity  of  brass  and  other  copper-zinc  alloys 221  368 

bronze  and  other  copper-tin  alloys 214  361 

Modulus  of  elasticity 174  2:6 

of  tin 179  294 

rupture 163  262 

Muntz  metal 88  160 

Nickel  and  its  ores 49  84 

copper 101  181 

and  zinc 102  182 

German  silver 102,  138          182,  215 

ores 49  84 


57O  INDEX. 

ART.  PAGE 

Nickel  and  its  uses 50  86 

Odor  and  taste 21  28 

Ordnance  bronze  [See  Bronze]. 

Ores,  aluminium 51  88 

antimony 47  82 

arsenic 55  95 

bismuth 48  83 

calcination 3  9 

copper,  distribution 29  42 

sources .  . . 31  44 

reduction 32  47 

distribution,  laws  of II  17 

fluxes 5  12 

indium 56  96 

lead 44  78 

smelting  galena. . . 45  79 

magnesium 54  94 

manganese 57  97 

mercury 52  90 

[See  Metallurgy.] 

nickel 49  84 

platinum 53  92 

reduction 3,4  9,  1 1 

roasting 3  9 

smelting 4  n 

tin,  sources  and  distribution. 37  64 

reduction 38  64 

zinc,  sources 40  40 

smelting 41  41 

Oriental  bronze 78  140 

Oxidation 70  124 

Pewter 126  202 

Phosphor-bronze 81  143 

abrasive  resistance 193  314 

tenacity 192  312 

Platinum 53  92 

and  iridium 128  203 

Preparation  of  alloys 134  210 

Prices  of  commercial  metals '.  59  99 

Proportioning  for  shock 155  255 

Rare  metals 58  98 

Reduction  of  ores  \See  Ores] 3,  4  9,  n 

Resilience 154  252 

of  brass  and  other  copper-zinc  alloys,  compared. . . .  240  409 

bronze  and  other  copper-tin  alloys,  compared 211  353 

[See  Elasticity,  Elastic  Limits.] 

proportioning  for  shock 155  255 

Resistance,  conditions  effecting  [See  Table  of  Contents,  Chap. 

XIII.]. 
brass  and  other  copper-zinc  alloys  [See  Table  of 

Contents,  Chap.  X.]. 
bronze  and  other  copper-tin  alloys  [See  Table  of 

Contents,  Chap.  IX.]. 

Copper-tin-zinc   alloys   \See    Table    of    Contents, 
Chap.  XL]. 


INDEX. 


571 


Resistance,  Kalchoids  and  other  copper-tin-zinc  alloys  [See 

Table  of  Contents,  Chap.  XI.]. 
mechanical  treatment   [See  Table  of  Contents, 

Chap.  XIV.]. 
non-ferrous  metals  [See  Table  of  Contents,  Chap. 

VIII.]. 

tin-zinc  and  other  alloys  [See  Table  of  Contents, 
Chap.  XII.]. 

annealing,  effect 276,  277,  293      484-487,  526 

compressive,  brass 232  385 

bronze 190,  208  309,  346 

chill-casting 275  483 

copper 170  278 

[See  Mechanical  Treatment,  below.] 

non-ferrous  metals 157  255 

conductivity,  electric,  of  alloys 68  120 

bronze 216  363 

thermal 17  21 

alloys 67  118 

bronzes.    216  363 

[See  Heat,  below.] 

ductility,  brasses,  compared 244  412 

bronzes,  compared 215  362 

kalchoids  and  other  copper-tin-zinc  al- 
loys  256  434 

elasticity,  modification  by  heat 272  480 

moduli  for  brass  and  other  copper-zinc 

alloys 221  368 

moduli  for  bronze  and  other  copper-tin 

alloys 214  361 

moduli  for  copper .'  174  286 

tin 179  294 

Wertheim 184  300 

elastic  limits,  brass  and  other  copper-zinc  alloys .    241  409 

bronze  and  other  copper-tin  alloys.   213  358 

exaltation 306  550 

non-ferrous  metals 152  249 

[Sfe  Stress,  below.] 

fluctuation  of  resistance  of  bronze 282  489 

fusibility 25,  63  36,  no 

hardness  of  bronze  and  other  copper-tin  alloys.  19 1,217  3*1  >  363 

heat,  conductivity  [See  above.] 

latent ! 26  36 

modifications  of  elasticity 272  480 

stress 273  481 

temperature  of  casting 278  488 

tenacity , 269-271  476-480 

mechanical  treatment   [See   Table  of   Contents, 

Chap.  XIV.]. 
cold-rolling,  Lauth's  pro- 
cess    296  529 

cold- working 294  527 

bronze 310  550 

iron 309  555 

Dean's  process,  condensa- 
tion    297  530 

forging,    drop,  hydraulic 

291,  292  524,  525 


572  NDEX. 

ART.  PAGE 

Resistance,  mechanical  treatment,  frigo-tension 301  540 

hammering 303  543 

Lauth's  process,  conden- 
sation     .   290  523 

rolling 291,  303  524,  543 

Uchatius'    process,    con- 
densation    298-300  531-540 

wire-drawing 295  527 

resilience 154  252 

brass  and  other  copper-zinc  alloys 240  409 

bronze  and  other  copper-tin  alloys. ...   2il  353 
[See  Strain-diagrams,  belowJ\ 

rupture,  modulus 163  262 

theory 161  259 

safety-factors 148  244 

shafts  [See  Torsional,  below] 166,  235  268,  392 

shearing,  of  copper 170  277 

shock,  non-ferrous  metals 153  251 

proportioning  for 155  255 

strain-diagrams,  brass  and   other  copper-zinc  al- 
loys, tension,  transverse 237,  238  404   406 

strain-diagrams,    bronze    and    other    copper-tin 
alloys,  tension,  compression,  and  transverse. 

206,  208,  209     346,  347,  348 
strain-diagrams,  kalchoids  and  other  copper-tin- 
zinc  alloys 254  429 

stress,  intermitted  effect  on  elastic  limit 285  508 

produced  by  change  of  temperature 273  481 

repeated,  effect  on  strength 287  515 

steady  and  uninterrupted 284  500 

uriintermitted,  effect  on  deflection 283  502 

elastic  limit 285  508 

variable  effect  on  elastic  limit 286  512 

tempering,  effect  on  density  and  tenacity. . .    276,  277  484-487 

tensile  [See  Tenacity], 
time  [See  Stress,  above], 

time  of  loading,  effect 279  489 

torsional,  of  brass  and  other  copper-zinc  alloys.  .   234  391 
kalchoids  and  other  copper-tin-zinc 

alloys 246  414 

non-ferrous  metals,  alloys 165  267 

shafts 166,  235  268,  392 

tin 180  294 

zinc 182  298 

transverse,  brass  and  other  copper-zinc  alloys  . .  .   233  387 
bronze  and  other  copper-tin  alloys. 

197-205  320-341 

copper  173  284 

formulas 162  260 

kalchoids   and  other  copper-tin-zinc 

alloys 246  414 

non-ferrous  metals 159  256 

strain  diagrams,  brass  and  other  cop- 
per-zinc alloys 238  406 

strain-diagrams,    bronze    and    other 

copper-tin  alloys 209  348 

time,  effects 279  489 

tin 178  292 


INDEX. 


573 


ART.  PAGB 

Resistance,  transverse,  zinc 182  298 

wire-drawing 295  527 

Rolling 291,  303  524,  543 

Riche,  hardness  of  bronze 191  311 

Roasting 3  9 

Rupture  [See  Resistance]. 

modulus 163  262 

theory 161  259 

Safety  factors 148  244 

Shafts,  strength  of 166,  ^35  268,  392 

Shearing,  resistance  of  copper 170  277 

Shock,  non-ferrous  metals 153  251 

proportioning  for 155  255 

[See  Resilience.] 

Silicon  and  copper 109  187 

Silicon  bronze no  188 

Smelting  [See  Metallurgy]. 

Solders 140  216 

Specific  gravities  of  alloys 62  108 

brasses  and  other  copper-zinc  alloys. . . .   243  412 

bronzes  and  other  copper-tin  alloys 212  355 

densities  and  weights 19  25 

Spence's  metal 129  204 

Standard  alloys 141  218 

Stereotyping 137  214 

Sterro-metal 220,  247  368,  415 

Strain-diagrams. 150  247 

of  brass,  tensile 237  404 

transverse 238  406 

bronze,  compressive 208  346 

tensile 206  344 

transverse 209  348 

kalchoids  and  other  copper-tin-zinc  alloys.  254  429 
Strength  [See  Resistance]. 

Stress,  intermitted,  effect  on  elastic  limit 285  508 

produced  by  change  of  temperature 273  481 

prolonged,  effect 280,  281  492-497 

repeated,  effect  on  strength 287  515 

[See  Resistance.] 

steady  and  unintermitted 283  500 

unintermitted,  effect  on  deflection 284  502 

elastic  limit 285  508 

variable,  effect  on  elastic  limit 286  512 

Structure  and  composition  of  metals 158  256 

Taste  and  odor 21  28 

Temperature  [See  Heat]. 

Tempering  [See  Annealing] 293  526 

effect  on  density 276  484 

tenacity 277  487 

Tenacity,  annealing  effects 277,  293  487,  523 

bell-metal '189  308 

brass 231  384 

strain-diagrams 237  404 

bronze 207  344 

condensation 297-300  53O-54O 

modification  by  heat 270  477 

ordnance,  Anderson's  experiments 188  308 


574  INDEX. 

ART.  PAGB 

Tenacity,  bronze  ordnance,  Wade's  experiments 187  306 

strain-diagrams 206  344 

cold-rolling,  effects 296  592 

working,  effects 294  527 

upon  bronze 310  556 

iron 309  555 

copper 167  270 

modifications  by  heat 269  476 

[See  Compression,  Ductility.] 

forging  . .  , 291,  292  524,  525 

frigo-tension 301  540 

hammering 303  543 

heat  modifications,  bronze. 270  477 

copper 269  470 

non-ferrous 268  476 

various  methods 271  480 

kalchoids  and  other  copper-tin-zinc  alloys 255  430 

non-ferrous  metals,  modifications  by  heat 268  476 

Ehosphor-bronze 192  312 
See  Resistance.] 

rolling 303  543 

cold  [See  Cold-rolling,  above]. 

strain-diagrams,  brasses 237  404 

bronzes 206  344 

tempering,  effects 277  487 

thermo-tension 293  526 

various  metals,  modifications  by  heat 271  480 

wire-drawing 295  527 

Ternary  alloys,  grey , 265  450 

Tests  [See  Investigation]. 

Thermal  conductivity 67  118 

Thermo-tension 293  526 

Thurston  [See  Alloys,  Thurston]. 
Time  [See  Stress]. 

Time  of  loading,  effect 279  489 

Tin  and  antimony 119  198 

bismuth  and  copper 112  188 

lead 125  202 

and  lead 123  202 

zinc 124  202 

and  bismuth  and  lead 117  193 

commercial 39  66 

and  copper  [See  Bronze]. 

and  iron 96  174 

zinc 94,  248,  262     172,  416,  447 

distribution 37  64 

elasticity,  moduli 179  294 

fusible  alloys 117  193 

and  lead in,  188  120,198 

resistance 177  288 

torsional 180  294 

transverse 178  292 

sources 37  64 

stress  prolonged,  effect 280  492 

ternary  alloys,  grey 265  450 

and  zinc  .  .    121,  263,  264      2OI,  449,  450 

and  iron 113  189 

Torsional  resistance  of  brass  and  other  copper-zinc  alloys  . . .   234  391 


INDEX.  575 

ART.  PAGE 

Torsional  resistance  of  bronzes  and  other  copper-tin  alloys. .  205  341 
kalchoids   and   other   copper-tin-zinc 

alloys 251-259  419-442 

non-ferrous  metals 165  267 

shafts 166,  235  268,  392 

tin 180  294 

zinc 182  298 

Transverse  loading,  formulas 162  260 

time  effects 279  489 

resistance,  brass  and  other  copper-zinc  alloys. . . .   233  387 

bronze  and  other  copper-tin  alloys. . . .    186  306 

copper 173  284 

kalchoids    and    other    copper-tin-zinc 

alloys 246  414 

tin 178  292 

zinc 182  298 

strain-diagrams,    brass    and    other    copper -zinc 

alloys 238  406 

bronze    and    other    copper-tin 

alloys 209  348 

stress,  non-ferrous  metals  159  256 

Uchatius'  deductions 300  540 

experiments  on  compressed  bronze 299  533 

method  of  condensation  of  metals 298  531 

Wade's  experiments  on  gun-bronze 187  306 

Weights  and  densities 19  25 

Wertheim  on  elasticity 184  300 

Whitworth's  process  of  compressing  steel 289  519 

Wire-drawing 295  527 

Zinc  and  antimony 124  202 

copper  [See  Brass]. 

and  iron 95  174 

and  tin 113  174 

and  tin 248  416 

history 40  40 

iron  and  tin 96,  113  174,  189 

metallic 42  73 

nickel 102  182 

ores 41  41 

smelting 41  41 

sources 41  41 

strength 181  296 

stress  prolonged,  effect 280  492 

ternary  alloys,  grey 265  450 

tests 182  297 

tin 151,  264  201,  449 

density  and  strength 265  450 


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